First off, we got secure pet trading. Basically, when you transfer pets now, it does the skill check first. Once you get a successful skill check, then a trade window comes up with you offering a scroll that says something to the effect of "Smaug/a horse owned by Johnny". Then, you can either accept gold (since it is a secure trade window) or give it away free.
Creatures with less than 35 taming can no longer be made happy by commanding them. No biggie, horse food is free for the picking in Delucia or Orc Fort. Basically, you can no longer spam such creatures to happiness. This does not effect more difficult creatures that have a taming difficulty over 35. Those creatures can be commanded to happiness as long as you continuously succeed.
I've heard reports that certain pets (such as horses) are now vanishing after they go wild. This is most likely related to the new animal decay. Basically, creatures that do not get targeted or receive damage after a certain period of time will die. While horses and such are still loyal to the owner, they won't die. But since they have not been targeted in a long time, they will "decay" once the loyalty depletes.
Part of the last publish was reverted. Transferred pets will no longer increase in control difficulty. However, if it is retamed, you still have a chance of taking a control difficulty penalty. The only way to negate this is by "calming" the pet. "Calming" does a skill check on your taming and animal lore. If both skills are high enough, you will calm the creature and avoid the control difficulty penalty.
They put the "you have no chance of taming this creature" back into the game. It was sad watching people try to tame a horse for hours, even though they had no chance of taming it in the first place.
Dex changes to healing and possibly vet? I have a character with 100 dex and healing. I don't see much difference in healing times on myself, but there is a significant difference in healing a partner. I don't know how this will effect veterinary, since I have 25 dex. It is my understanding that with 25 (or lower) dex, you basically have the same healing rate you did before the publish. You simply get a bonus if you have more dex than that. It is debatable as to whether or not this effects vet or not. But logic dictates that it does, as both healing processes are achieved by the use of bandages.