Can anyone explain why Blizzard made several slots and even talents increase run speed when none of them will stack? Trinket, Boots (equip & enchant), Meta Gem, talents.

I understand how it "frees" up other slots, but what if you like the use: on the Golden Hare? What if you like the +12 spell damage (or the attack power equiv) on the Meta Gem? I don't really understand why Blizzard thought it was so important to cap the stack so low when mostly everyone has access to these things.

Movement speed buffs are some of the most powerful available - mob speeds and such have to be balanced for how fast players move, and obviously PVP as well. It's far easier to develop around if there's a hard cap to non-conditional move speed bonuses.

Because speed kills - if they stacked, then you would be obligated to use as many as possible to achieve the maximum possible effect, which would end up in MORE equipment slots being dictated by necessity than before.

You could argue some system of (sharply) diminishing returns, but its a heck of a lot simpler to just take the greatest modifier.

So why not leave it as it was? There were no equip trinkets with Run Speed increase pre-TBC (IIRC), no gems to increase speed. Talents have always been dismissed and pretty much made useless, since the enchant you could get on boots was not worth the points spent on the run speed talents (for the class[es] that have them).

Now all they did was create more things that cancel out all but one. Can anyone think of any other equip mechanic that suffers in this fashion?

Depends. I value the +speed on metagems as being worth either 6 stamina or 6 agility, depending on which boot enchant you'd be more likely to get. For a DPS caster, which gem is really that much better? For a rogue?

24 AP and 6 agility vs +3 damage and a chance to stun? It's more direct damage than +3 damage is on all but the fastest weapons, plus the bonus to crit and dodge; if chance to stun isn't useful, the 24 AP + speed gem is certainly better. While in some cases it's slightly arguable (2% instacast vs 12 spell damage and 6 stamina?) they're certainly quite usable choices, especially since they're basically free.

More move speed effects provide more options by creating more combinations - I can get a movespeed metagem and enchant Stamina or Agility or whatever on my boots, or i can get the boot enchant and get a different metagem, or I can use a movespeed trinket and have a different enchant AND a different metagem. More options make for more interesting decisions.

I personally think that there are better meta gems for just about everyone over the one's with minor run speed.

I really don't understand what you are complaining about or why this warrents a post. If you like the items then use them. If you don't like them then don't use them.

Because then it would just be like you were playing CS with a speedhacker.

Options. If Blizzard only ever provided one way of getting a run speed increase, people would complain that they were "pigeon holed" into wasting a bag space / enchant / meta gem or whatever it was. For a Rogue especially, it's nice having a number of different ways to pick up run speed increase (which I would certainly argue is a necessity more than a luxury).

Exactly my feeling. The run speed meta gem is great in my Hallowed Crown when I'm called upon healing in 5-mans or whatever, as it frees up my boots for a +12 stam enchant instead.