Sorry for posting a link to an external site, but I didn't want to hand type out everything:
https://www.wow-petguide.com/?News=223
Those are some side by side comparisons of old vs new. Stampede Effects, Righteous Inspiration, etc.
Some early alpha ability changes
Carry Pet Experience Reference Guide:
http://www.warcraftpets.com/community/forum/viewtopic.php?f=10&t=8829
http://www.warcraftpets.com/community/forum/viewtopic.php?f=10&t=8829