Only for some specs (like prot paladin bread and butter abilities) does it reduce cooldowns. But, for most/all specs it reduces the global cooldown, which is the time you have to wait between using two abilities.
I see. I’m lazy so I just copy/paste and have different sets already made by the addon part.
I really wish they’d make the game simpler, having to sim everything is just… tiresome. And it takes away form the magic of earning loot since, well, it sims 10% less so garbage it is.
Haste decreases spell cast times, time between HoT and DoT ticks, cooldown on some abilities (those with green cooldown text) and global cooldown
Mastery works differently for each spec
Versatility increases damage and healing DONE; and also gives half as much reduction of damage taken
Crit and haste have also additional functionality for some classes. For example, destro warlock’s Chaos Bolt always crit and crit stat increases damage done by Chaos Bolt. Haste increases frequency of some procs (can’t name any right now, but I’m 100% sure) - I mean, if some passive triggers 3 times per minute haste can increase amount of procs to 4 times per minute.