If you’ve played any modern DIKU-style MMO (like World of Warcraft or Rift) you’ll probably have come across the concept of cooldowns. Some abilities will be rather powerful but only available to your character once in a defined timeframe. A Paladin in WoW can use her Lay on Hands spell every 20 minutes and a Rogue has Cold Blood available every 2 minutes. The idea behind this is to give players access to excitingly powerful effects without making them too strong in the process. Frankly, current implementations of cooldowns do many things wrong.
The biggest offenders are those abilities with long cooldowns. Imagine having a go at a boss fight, failing, running back, wanting to fight again… but being unable to because a relevant ability isn’t off cooldown yet. If you are as impatient as I am, this can be really annoying and it isn’t really necessary for the original intention. Using an ability once each fight is no more overpowered than having the ability at all, yet we are often faced with the decision of waiting for an ability to be ready or trying without out it. That is not an interesting decision at all.
Now, things aren’t as easy as simply lowering the cooldown timers on those abilities. My warrior in Rift, for example, has an ability that heals her full instantly but has a cooldown of 10 minutes. This is clearly meant to be used as an oh-shit button for when things don’t work the way you planned. Going into a fight without this ability available is unnecessarily risky and waiting would always be the safer and more intelligent play. Also, very boring.
Reducing the timer on the ability would cause multiple problems though. For one, I would suddenly be able to use it multiple times in a fight which would be a clear increase in power. I could even plan fights around the cooldown on the ability just like tanks in World of Warcraft do for harder boss-fights. For another, my character would get an unfair advantage in PvE, being able to care very little about health because she could simply heal up on demand instantly. Finally, PvP fights against such an empowered character would become incredibly annoying, essentially forcing the enemy to kill you quick or be faced with the task of killing you all over again.
World of Warcraft has addressed this issue in many cases by weakening the abilities and reducing their cooldowns appropriately. This, while effective, counteracts the original idea behind the abilities – that of a very powerful effect for show. Assuming that the latter is desirable, a simple reduction in cooldown times seems pointless.
Another approach is the once-a-fight system that WoW has placed on the use of consumables. Before that system was created, players could drink multiple mana potions in a fight (whenever the rather short cooldown was over.) Nowadays, drinking a potion will make you unable to drink another one until the fight ends. Such a system would be quite sensible if the game was only about boss fights, but one has to keep solo-play in mind as well. If your character could heal up instantly for free after every group of enemies, non-lethal loss of life would be irrelevant. While something is to be said about such a system to improve the flow of gameplay, it would be quite unfair if only a few players would have access to it.
The final system I can come up with is that of resetting cooldowns on death. The effect of that can be (somewhat) observed on WoW’s Heroism spell. The spell itself is on a rather short 5 minute cooldown, but everyone affected by it is given a 10 minute debuff that prevents them from getting the effects of Heroism again. This debuff is removed upon death. This way, players can’t (usually) use Heroism more than once in a fight, but still don’t have to wait for Heroism timers much after a wipe.
Both this system and the previous one have scaling issues. The effect of a once-per fight ability will be much more significant in a short fight than it will be in a long one. While a variable effect of a group-wide effect like Heroism isn’t all that problematic, individual character abilities might be viewed as unfair by the players if only some character lose a lot of damage potential in long fights, for example. Then again, players will complain about such things anyway and the problem exists with longer time-based cooldowns as well, so maybe this is a problem that can be ignored.
Overall, I feel that pure time-based cooldown abilities have to go away sooner or later, at least when they are on relatively long timers. A 2-minute timer can make for interesting decisions; a 10 minute one is just annoying. Either death-based or fight-based resets should be added to more powerful abilities though which one is appropriate probably has to be examined for each individual ability.