Hunter
When your pet gains a level, it will automatically gain a new rank of Growl if one is available at that level. The only thing you really need to manage is which talents to choose... and keeping your spore bat fed and happy. You don't learn skills from (disposable) beasts any longer, and the only thing to do at the Pet Trainer is untalent your pet. (Source)
We didn't want hunters to have spend a big chunk of talent points just to get pet resistance up to where it is in Burning Crusade. So pets will have some amount of inherent resistance. We're not sure how much that will be yet, but it should be enough that your pet doesn't feel fragile. If you want a truly magic-resistant pet, you can top it off with talents. For now at least the lower ranks of the old resistance skills are just free like Growl and Cower. (Source)
There are talents in all 3 pet trees that you can invest in if maintaining happiness is a problem (or just annoying) for you. We're also trying to give you a few more options to keep your pet alive, such as more Avoidance and reduced spell damage, and even more ways to heal your pet. Of course you can always choose to focus directly on more damage and hope your pet survives long enough to make good use of it. (Source)
Think of your pet bar as just shortcuts to your spellbook. It doesn't really matter if an ability is on the bar or not. It can be cast or autocast directly from the spellbook, and unfortunately all new abilities start with autocast defaulted on. This is something we might be able to fix, but in the meantime, peek at your pet's spellbook whenever it gains a level to make sure nothing has changed. Cower can surprise you, because it/si something a lot of players passed on before -- understandably, because even if effective it's not a very fun thing to spend points on, which is why we just give it away now. (Source)
We haven't done a major pass on threat generation yet for any of the classes. We realize it was very easy in BC for hunters to pull aggro off of their pets. You can probably tell from some of the pet talents (including the ones that just grant more pet dps) that we want pets to be able to hold their own threat against a hunter. This is especially true when it's just you and Bitey out on your own, but ideally a tanking pet with the proper spec will be an effective offtank for 5-player instances, or even a main tank under some circumstances (say a group quest perhaps). (Source)
so wie es aussieht scheint sich bis zum release ja noch ne menge bewegen zu wollen was das pet angeht...;)