Without damage meters we don't know exactly how good or bad it is. Maybe once we can it will be more clear but right now I'm not super impressed. Maybe if they doubled the cd or something. I did find a comment that broke down the math and it kind of confirms my fears:
[/center]As it is right now (3 second cast, 10 minutes cooldown), it is barely notable; if you were say a SV your pet would do about 20% of your overall damage; now considering 4 more pets in end game gear ( ~40k dps),
each pet would deal 40*0.2 = 8k dps, so all your pets would deal 8*4 = 32k dps
As stampede has an uptime of 10 seconds, the total theorical damage would be 32*10 = 320k dps
Now, considering a reasonable travel time of 2seconds to the target, it would end up dealing 32*8 = 246k dps
Finally, as it has a cast time of 3 seconds and that you alone deal 32k dps, it would mean a 96k dps loss for its casting time
Result being: Stampede would add only for about 246 - 96 = 150k DPS in a whole fight. A cd like bestial wrath gives me way more dps than that in 10minutes. Ofc this is just a rough calculation, its subject to variations such as stabled pet cds, the fact that BM pets are stronger etc
http://mop.wowhead.com/spell=121818/stampede
Don't get me wrong, hunters are looking to be amazing in MoP barring any future nerfs....I mean rebalancing, lol....and I'm overall loving my hunter on Beta right now. It's just Stampede is our big new thing. It's our new toy. I want it to be as big of a damage increase as it is a fun new ability. I hope the tweak it a bit before live so it will feel like the big new cd it is. Right now its sort of lackluster.