I have experience playing the low levels. I can briefly summarise the impact as follows:
- It will make encounters much harder. With many characters dying in combat, and possibly a few total party kills as well.
- This can be demoralising, but some players might be up for it.
- But something perhaps easily overlooked is that it removes a wonderful suspense building mechanic from gameplay. With current rules, a character going down leads to a change in tactics to keep the party member alive. By removing death saves, this falls away. And the only decision is: Is it time to flee, or can we still win this?
Characters in our party are regularly taken down (which would mean death with the house rule) and require in-combat healing to bring them back into the fight. Failure to do so in some cases would probably have resulted in total party kills.
In your comment on Dale's answer you consider:
players were encouraged to retreat if the going got tough
The problem with this is that there's not necessarily enough time to make an escape. The fact is that even as it stands (without the house rule): "level appropriate" monsters have a decent chance of 1-shot killing most level 1 characters. (When I say decent chance, I'm not even talking about needing a critical hit.)
NOTE That a single CR 1 monster is considered level-appropriate for 4 level 1 characters.
Consider a Specter (CR 1): It does 3d6
damage with +4 to hit. This is only an average of 10.5 damage. But it's special ability states that if a CON saving throw is failed, the target's maximum hit-points are reduced by the same amount (and if reduced to zero, the character is dead).
Of course if you and your players are up for a much more difficult challenge, then then feel free to tweak accordingly.
However, changing the death-saves rule is not the only way to do so. Remember that removing death-saves also removes a tension creation mechanism of combat. So instead of removing death saves, consider the following ideas:
- Have your monsters fight more "intelligently". Let them make good tactical decisions, and you'll see difficulty ramp up without any extra work.
- Tweak difficulty of encounters by adding monsters, or using stronger monsters. This might require a little more planning on your part, because it can be a little to easy to overdo it.
- Reduce the character's opportunities for rest a little. This means they rarely recover their abilities between encounters. It has a similar effect to the second point but is possibly a little easier to manage.
Based off of DDAL1 modules...
The Table:
\begin{array}{l c l}
\text{Total GP Expended} & \text{Level} & \text{(Expenditure for next level)} \\ \hline
0 & 1 & (700) \\
700 & 2 & (1,000) \\
1,700 & 3 & (1,350) \\
3,050 & 4 & (1,850) \\
4,900 & 5 & (2,500) \\
7,400 & 6 & (3,500) \\
10,900 & 7 & (4,750) \\
15,650 & 8 & (6,500) \\
22,150 & 9 & (8,750) \\
30,900 & 10 & (12,000) \\
42,900 & 11 & (16,500) \\
59,400 & 12 & (22,500) \\
81,900 & 13 & (31,000) \\
112,900 & 14 & (42,500) \\
155,400 & 15 & (58,000) \\
213,400 & 16 & \\
\end{array}
The Method:
I went ahead and tabulated the possible XP to earn and possible treasure haul2 for each of the two-dozen or so DDAL modules I've got on hand.
Each module is designed for one of the following level spans3: 1-2, 1-4, 5-10, or 11-16.
From the XP earned in each I calculated a fraction of the indicated level span that would be "traversed" by completing the module, and used that to extrapolate how much gold would accrue to one gaining a level in that span.
I then weighted each by the recommended hours of play4 and ran a power regression.5.
Finally there's just a bit of rounding to make the numbers... round.
The Application:
Full confession: I don't think this ^^ is the best way to come up with these numbers.6 But I think it's a way and figured it's worth letting voters see so that wiser heads than mine can decide.
Those numbers are just... insane. Dropping that much cash--per adventurer!--onto the population of Barovia is just ridiculous. I know that D&D doesn't try to model any sort of functioning economy, but this is a bridge too far for my credulity. So you've got to find ways to ameliorate it. Perhaps use this table as a party table, so that once PCs have dropped 700gp everyone bumps to level 2? Perhaps adapt Delta's advice and switch to a silver standard (for XP) so that this all drops by an order of magnitude? Or perhaps...
magical items should be allowed as part of this scheme. Buying everyone a round and carousing for a night doesn't feel (to me) very different from rescuing a villager from weres and tossing a potion of healing their way. But this could also be a place where you can exert a GM's thumb on the scale, since the "values" of any items that the players disposed of in a way that buffed their renown aren't terribly standard. (And to that end, I'd recommend the Sane Magic Item Prices index; it may not be perfect, but it's waaay better than following the DMG's loose guidelines.) And now you've given players the interesting choice between hanging onto their widget of frobbing or "cashing it in" to level up. (Or level everyone up, per point 2!)
1 - Dungeons & Dragons Adventurers League, WotC's organized play program that was (and sort-of is?) active during 5e. The modules published through this program followed a rough set of guidelines for XP and treasure given out, and I'm using this as an insight into what WotC employees (Chris Tulach, specifically, perhaps with input from other designers?) thought was a good pacing of treasure accumulation by level.
2 - only coinage; since you indicate your players won't really be able to "cash in" any magical items, we're going strictly off of currency here. But more on this later.
3 - I'm using the term "span" rather than "tier" as "tier" is a defined term in 5e (PHB p.15) and these modules don't all correspond to tiers. It feels clunky, but I didn't want to conflate the ideas.
4 - Some modules--only in the lowest two spans--are recommended for two hours, most are recommended for four. This then has the effect of dialing back the impact of these smaller modules. However, there are many more of them (fifteen in 1-2 and 1-4) than in the higher levels (six in 5-10, one in 11-16) so the model's still drawing more of its info from those levels.
This weighting toward low-level information strikes me as fine in one way, as that's where the majority of play tends to happen. On the other hand, this means that any "errors" in the model are likely to appear at the high end, where it's going to take a while for you to notice and be really hard for you to fix: "oh, dear, we've been on level 10 for five sessions now, and are only halfway through. And I want them at 12 to face Strahd et al. for the last time and there's almost nothing left to explore!"
5 - power regression based on eyeballing this curve.
6 - I can think of one better way, but it's going to have to wait until I get my copy of CoS back from a buddy.
Best Answer
You Should Be Dead, But...
Save-or-die mechanics are pretty awful for straight-up challenges. I mean, you wouldn't exactly get a lot of tactical thrills from a game that boils down to "Flip a coin to see if you lose," would you? But that's not the only way they've been used.
Practices and opinions vary pretty widely in the OD&D/OSR community, but one way of looking at "save-or-die" is that the saving throw is the "second chance" mechanic.
Proponents of this approach say that falling into lava or getting stabbed through the chest ought to be lethal, so really the game is about avoiding those things altogether, not surviving them if they do come to pass. And the saving throw is there to decrease character death without removing the actual threat.
What this means in play and adventure design, though, is that you can't make save-or-die situations a thing that just happens to the PCs. Rather, you have to telegraph the threat and the PCs' main goal is avoiding it altogether.
For example, if the PCs are entering the lair of a gorgon ("medusa" in D&D terms), they'll know it from the crazy-looking 'statues' all around. The challenge is sneaking past the gorgon, or fighting her without looking at her (probably using a trick of some sort), or even negotiating with the clever and cunning monster for safe passage. If they're having to roll saves to avoid petrification at all, it means they're screwed up the actual plan badly.
Unfortunately, this approach doesn't really work if you want an adventure to involve a series of challenges the PCs are mostly expected to face head-on — because that's your idea of heroism in the story, because you want to play some thrilling tactical battles, &c. What happens then is the players will be rolling those saves not as a failure consequence but as a result of engaging the scenario at all, and of course some will fail and die kinda out of nowhere. That's one of the reasons 4th Edition D&D in particular removed the "save-or-die" angle from the game.
Adding More Second Chances
So, you don't want characters to die all the time, but you want them to feel like their lives are constantly at risk (which is a bit of a contradiction, yes, and it's good to recognize that).
Well, if you want to maintain the "threat" of death, I recommend trying to lessen its occurrence, not its impact. Dependable resurrection mechanics essentially redefine "death" to "XP/loot penalty" or "sidequest" (it's worth noting that some older D&D editions had "system shock" rolls to keep resurrection from being a sure thing). If you want death to be scary, I think it should have some finality to it. Focus on giving players a way to narrowly cheat death rather than a way to straight-up undo it.
One way to do it is to bolt on an explicit death-cheating mechanic. Some established patterns include:
One approach that feels rather "old-school" is the "death and dismemberment" table. Make a random chart of nasty things that happen to you. Death is on there. So is other stuff, though. The idea is to replace death with "a chance of death or maybe you just get screwed up some other way." Here's an example with a variety of brutal but non-lethal outcomes.
Many games try to balance gritty combat with survivable heroes using limited metagame currency for avoiding failure consequences, in the style of WFRP's Fate Points. If you can straight-up rewrite the outcome with a point, then they're kinda like 'extra lives.' If you want to make it less of a sure thing, have the points give you a reroll instead.
I recommend using a pure metagame resource instead of something in the fiction (like resurrection scrolls or whatever) because I think creating fictional elements that allow you to defy death necessarily draws a lot of attention to those elements, and invite the PCs to go messing about trying to figure out how to 'game' the system (e.g. score more resurrection scrolls so they can't run out).
Save-Or-Die and Converting Between Editions
Another thing to note is that the different D&Ds have different save mechanics.
Be mindful of this when converting: mid-level characters in OD&D or an OSR game might actually be way, way better at making their saves than equivalent characters in a D20 game.