The problem with Heal is that it doesn't scale well once you get to the higher levels. It's designed to do healing based on a level 18 base HP bar, but that's not taking into consideration any items in the post-18 game. Plus it's countered by reduced healing effects like Ignite, Katarina's Death Lotus, Miss Fortune's Impure Shots, etc. While all heals are affected as such, in this case it's a tad more game breaking since it's eating up one of your summoner slots.
Revive is generally a poor choice due to the fact that it requires you to be dead in order to use it. Obviously you want to avoid being dead in the first place. While you generally can't avoid at least a handful of deaths in a game, you don't want to count on Revive being used as quick-back from death, compared to another skill which could have prevented that death in the first place.
That all being said, there are a few champions that can utilize these skills particularly well. A lot of support characters can utilize Heal quite well like Taric, Soraka, Sona, Alistar. Combining Heal with their built-in heal spells can provide an inordinate amount of burst healing which can be deceptive to the enemy team.
Revive is a good gimmick choice for a Twisted Fate or Pantheon playing mid to push the lane early. Once you're 6, go for a skirmish with your 1v1 opponent. If you win, great! But if you die, no big deal. Immediately revive, buy (be ready!) and ultimate back in, using your Gold Card (TF) / Shield Bash (Panth) to stun and finish them off. You have the speed boost from Revive so they wont escape, and now you have a good 15-20 seconds to push the tower. If you're well organized, you can have your jungler come help, or a sidelane move off to come finish the tower if you cant, keeping a strong 2v1 in another lane.
Additionally, Revive can be extremely strong late game when respawns are 50+ seconds long. You can turn a potential tower / inhibitor kill into nothing after a bad teamfight that's left you with few to no allies left. However, usually you don't want to ASSUME this is the fact, because you could have avoided that situation with a different summoner skill in the first place.
Basically, they're situational abilities with their place, but generally they're overshadowed by some of the more popular abilities.
Combining two runes will give you a random rune of the same tier. Combining 5 runes will give you a random rune of the next highest tier. You cannot combine 5 tier 3 runes at once (as there is no tier 4).
The rune combiner is random. It doesn't matter whether you combine marks, glyphs, seals, or quintessences -- they all work with each other, and the output can be anything.
The idea is that, generally, runes themselves are priced such that it is slightly cheaper to generate a tier 3 runeset from your old runes than by buying the tier 3 runes on their own. For instance, the level 1 +AD rune is 15 ip, while the level 2 +AD rune is 80 ip -- if you bought 5 of the level 1 runes, combined them, and wound up with a level 2 +AD rune, you would have saved yourself IP.
Unfortunately, as mentioned earlier, this process is completely random. If you have tier 1 and 2 runes, by all means, combine them to higher levels; the rune combiner is just a way to possibly recoup the IP you spent on runes you no longer find useful, but it cannot be counted on to give you what you want. You might luck out and combine 2 random runes into a +Dodge quintessence (very expensive!) -- or you might get a mana/5 Mark (with a tertiary stat, and probably not worth the IP cost of your combined runes).
It's very much a gamble, and you don't get anything exclusive from it, so use it if you need to get rid of T1 / T2 runes, and safely ignore it otherwise.
Best Answer
Yes, absolutely. The most copies of an individual rune you'll ever need is 9 (or 3 for Quintessences).