If we just chilled out tank damage, then healing would be a lot easier. While I know it's popular in this forum to claim that we only want to make life hard for the healers, I think in reality many of you would get bored or risk losing your spot when the raid didn't need as many healers.While I agree that giving tanks more hp in this current environment is would be a good thing, there's a lot here that I very much disagree with.
A better answer, in our opinion, is to increase tank health and have bosses hit hard but not as often. The end result would hopefully be that it took several big heals to bring a tank back up rather than a single Holy Light crit. Currently overhealing isn't particularly scary because mana is cheap and the risk of the tank (or anyone dying) on a given GCD is very real.
If you currently put say 3 healers on the tank that isn't because it requires that much healing per second to keep the tank alive. Instead, it's because with 3 healers hopefully someone will be always casting and can land a heal after big hit one but before big hit two, which would kill the tank. If a few hots or shields get stomped on along the way, oh well.
Ideally, you put 3 healers on the tank because it takes 3 big heals to get the tank back up. If you don't coordinate well or use a big heal when a medium heal would do, then you'd risk too much overhealing and ultimately running out of mana. You'd need to heal smart as well as just healing fast and big, which is what the current design really encourages.
I predict health pools of all players will go way up in Cataclysm relative to player damage and healing. Everything (meaning PvP too) would be slowed down just a little so that making the right choice would sometimes trump making the fast choice.
I'll also add that many players think 10-player raid healing is currently more fun than in 25s because you are often splitting duties with just one other person -- "You heal the tank. I'll heal the raid." In 25s you get more of that whack-a-mole feeling where you're competing just as much with other players to heal someone first and nothing feels very organized or efficient.
Source
First off, you can design healing to not be as hard and still use a lot of healers. This is entirely a failing of the development team, and pretty much a cop-out.
Forcing players to use healing strategies where "hopefully" someone lands a heal at the right time is horrible. The current system encourages spamming the *@#$ out of the tank, it does not encourage smart healing. Divine plea with a 50% heal reduction is bad; clearly they don't see how the vast majority of paladin healers use it. Beacon of Light is bad for the game; it very much encourages spamming and not smart play. Problems with healer mana stem from requiring stupid amounts of healing in order to keep people alive with luck rather than smart healing. AE just for AE sake and rediculously hard hitting bosses are new bad gimmicks; WoW didn't always have these on every boss. In my mind, this is more fun than heal-chain/rotations and smart healers still play better, but it could and should be designed better (and perhaps the current state of it's design now is a product of PvP influence?). It would be nice to even see a system where it was possible to see a boss that hits very fast for medium damage for variety.
10-mans are more fun to heal because the damage isn't as ridiculous, though it's also much easier to stack 3 healers for stupid healing fights and still meet dps requirements. Also, anyone saying "more fun" means that they have run both 10 and 25 which means that they are probably over-geared for a 10-man. I feel very strongly that our current 10-mans give out far too high itemlevel of gear in relation to the 25 man progression.