Well.....
Animal AI is being re-worked at present. Possibly some improvements will come in time for the dungeons update (next expected update) since better AI would mean that whatever monsters are in the dungeons will be more challenging. Domesticating and breeding of farm animals is planned and will be worked into the AI updates but I doubt if it will come before the dungeons however.
Survival as we've all come to expect from this game is going to be survival of the elements. Weather is coming but needs more tweaks. Cold weather and rain should increase the risk of hypothermia for sure.
Specialized storage has also been thrown out there, i don't know much for sure about what will come but I know there will be a new tool rack (that will actually show the tools paced).
I personally am in favor of weight limitations and reduced inventory in favor of relying on horses and horse-drawn wagons to help do the heavy lifting. I'm not sure if this is going to happen. There's still some debate as to how much "minecraftish" this game will be. I personally don't like the idea of being able to carry a forest of logs in my pocket but hey, its still a game. This one will probably not become as hardcore as some of us survivalists want but who knows? There is a lot of potential, the devs are great, and anything is subject to change in alpha
Horses are already modeled and ready to go, we are just waiting on the new player models to come. Other stuff is dependant on that as well for example, boats and a horse saddle, since new player animations are being designed to show interaction with all those items. I don't know for sure that a horse wagon is planned, I certainly would like to see one (so I can pretend to ride about like Gandalf). NPC humans such as thieves and merchants and more agressive ones are planned but also dependant on the new player models.
There's a lot of other stuff Red51 is doing in parallel such as the new Java API which will allow for better custom scripts and mod packs, the animal AI, the dungeons, and the character models (with boats, horses, new tools, and possibly a fishing rod and bow and arrow). There's so much additional work to be done but that's pretty much everything we are expecting over the next few months.
The pigs on trees and other such oddities are part of why the animal AI needs to be re-worked. Gotta be patient, it's a small dev team! 