Good thread.
I think plants could be maybe be bugged, they are kinda bugged now for many people where they go back to the first stage (a dirt pile) for no reason.
I agree about winter, placing a lot of animals outside and not in a barn might look nice in the summer, but that's not going to look great in the winter. You probably are going to end up building huge barns or something if you don't want your animals outside, and that might not look as good.
Balancing could be an issue, they have mentioned that they will add lot challenges to this one, and we know how well Maxis sometimes balances things...
Not a bug but I would not be surprised if autonomy could be an issue, your sims might go outside to hug the animals all the time or the animals will interrupt your sims...
