The Complete Warrior spellsword is an exceptionally weak class. Entry requires at least one lost spellcasting level, and getting to 4th level requires two more. Lost spellcasting levels are like death to a spellcaster; in most cases it is optimal to never ever not even then lose spellcasting. So to begin, let us keep that in mind.
Furthermore, after the publication of Complete Warrior, similar concepts were produced in Wizardâs Playerâs Handbook II with its duskblade, and in Paizoâs Ultimate Magic with its magus. Both of these are base classes, and their versions of Channel Spell (called Arcane Channeling and Spell Combat, respectively) can be used at-will, rather than Channel Spellâs tight per-day limit, and can even be used with a full-attack.
In comparison, the spellswordâs Channel Spell can only be used 3/day at Spellsword 4th, and it requires a move action, which means it will almost certainly preclude a full-attack.
To get 3 rays from scorching ray, the spellsword needs CL 11th. Getting into spellsword and progressing it to 4th causes three lost spellcasting levels, so heâs a minimum of 14th level at that point.
A barbarian at that level would have Strength around 30 while in Rage (18 to start, +6 from Greater Rage, +6 from a belt of giant strength), and could trivially use Power Attack quite safely for substantial damage. Using a two-handed weapon, heâs looking at around 2d6+40 damage for each attack.1 That matches your 47 damage exactly, but it could happen up to three times in one turn. Unless the spellsword lost even more spellcasting levels to get more, he can only use Channel Spell three times per day.
A spellcaster, meanwhile, could cast scorching ray for 12d6 damage... but it would require only a touch attack, and could happen at range. Touch attacks are dead-easy to make, so a spellcaster should hit with all three. This loses out on the weapon damage, but targeting touch AC is so much easier that the expected damage goes up, not down. But more importantly, a 14th-level spellcaster has much better spells to use. Disintegrate would deal 28d6 damage; thatâs an average of 98 damage.
And thatâs just pure damage; spellcasters are far more formidable when they donât deal damage. For example, he could easily haste the barbarian to give him another shot at that 47 damage attack, and itâd hit the druid, the druidâs pet bear, and the rogue, too â easily adding over a hundred damage per round just from the extra attacks all these people get to make.
So yes, youâve understood the rules of Channel Spell correctly, and no, itâs not powerful at all. Spellsword is considered to be an at-most one-level class (for +1 BAB, +1 level of spellcasting, and 10% ASF reduction), but taking more levels is a mistake, one that even Wizards and Paizo recognized and fixed by publishing duskblade and magus, respectively. To âdownpowerâ the character even more is a bad idea. The class itself already does that too well.
- Damage derivation: 2d6 (greatsword, average 7) + 1½Ă15 (Strength, two-handed) + 1 (enhancement) + 5 (collision property, mostly for easy number) + 12 (Power Attaack, taking â6 or â4 penalty in 3.5 or Pathfinder respectively) = 47. Note this uses only two items (+1 collision greatsword and belt of giant strength +6, 54,350 gp out of 150,000 recommended for that level) and one feat (out of five); the number could be much higher with a complete build.
These are certainly creative, but they are not things the spells are capable of.
Both Frostbite and Ray of Frost specifically 1) target a creature, and 2) cause damage. They do not create large, strong, solid quantities of ice or frost, let alone free-standing or shapeable quantities.
To do that, your player's character need to learn a different spell, because spells do literally only what they say they do.
Your player is definitely demonstrating creativity and I cringe to see that crushed, but how they're trying to bend/break these spells is diametrically the opposite of how the overall game functions. They are effectively trying to be more powerful than they've earned, nullifying the need to grow, earn XP, and learn newer, more powerful spells that do the new things they want to do. They're basically giving themselves power and treasure (which is what new spells are).
There are games that work this way â where you can narrate creative portrayals of magical effects and have them just happen â but those games aren't D&D 5e and they work differently, with different abilities and limitations permitting and gamifying those kinds of creative freedoms. They still have limits, but they're in different parts of how the game works â and D&D 5e for obvious reasons lacks limits in those places, and so has no built-in way to prevent freeform magic from taking over and nullifying large parts of the game if it's added to the PCs' abilities.
D&D 5e is a game about looking at your (limited) personal abilities and resources, looking at the (limiting) environment, and figuring out clever combinations of them in order to overcome those limitations and achieve your goals. Freeform creative magic upends that, and will make the rest of the game kinda break, as its basic motivation loop of striving against challenges, to gain new abilities, and using new abilities to overcome greater challenges will no longer loop.
(That said, you might have fun with that anyway â there is a long, long tradition of bending/breaking games until they are more like the game everyone in the group wishes they were playing â but it only works if everyone in your group wants the game to be that different game. If you're going to let this player run wild with their magic, pause and pay attention to how the other players are feeling, positive or negative, about this change from what they thought they were playing.)
Best Answer
I would say no, for several reasons:
Ray of Frost on the PFSRD.
Ray of Frost does not freeze things, by RAW. There are spells that specifically say that they cause certain elemental effects (for example, Fireball specifically says that it "sets fire to combustibles") but Ray of Frost is not one of them. While it might be able to cool water or make a very small amount of ice, I doubt that Ray of Frost would be able to freeze enough water fast enough to break a lock.
Actually making the water stay in the lock is non-trivial. If you have some way of keeping the water from spilling out of the keyholes, then this isn't as much of a problem, but I don't think much water will actually stay in the lock after you've poured it in.
From a balance perspective, allowing an easy way to break open nonmagical, traditional locks using two 0-level spells is kind of cheesy, and Knock is 2nd level. I might be comfortable with players using a 1st level spell creatively this way, and definitely if they can creatively use a 2nd level spell for this kind of effect, but I think that using 0-level spells for a 2nd level effect is pushing it. I realize that Knock does more than just open nonmagical locks, but there isn't anything below 2nd level that can open locks, so I feel like that's a good baseline for this effect.
I'm not sure this would actually work, at least not in a reasonable amount of time. While you could certainly make a lock stop working by freezing water in it, breaking the lock entirely requires much more pressure than ice can reasonably exert. I find it more likely that the iron or steel that most locks are made of would just force the ice out of the keyholes or into other open areas rather than break. In the related Mythbusters episode, it required liquid nitrogen (which is likely much colder than a 0-level spell), and it still needed an impact to break the lock.
This is much more situational, but some doors (especially doors designed for security) don't open just because the locking mechanism is broken. If a door has a deadbolt attached to the lock, then breaking the lock won't let you open the door anyway. And if this trick works in a particular world, then it's very likely that locksmiths will adapt to this technique, and make locks that stay locked after being broken.