The changes are pretty extreme.
Changing DVA to be less about tanking/shielding and more of an offensive tank is an... interesting choice.
It makes sense for the character, i guess, but i am not so sure if this goes well with her whole tank role...
We kinda are getting into Symmetra levels of role mismatch with DVA i am afraid.
EDIT:
Oh wait i am dumb, her defense matrix stays.
As for the Mercy change, i am all for it, but it seems like so much power.
Res being an ability instead of an ultimate, but only single target was already a big thing, but her new ultimate is something else alright.