McCree nerf and D.Va buff are both being talked about by blizzard.
i personally feel like d.va is in a really good spot right now and this is why:
in my opinion, she was made to be an almost exclusively offensive tank and she works best that way, kind of like winston. the only way to 100 to 0 targets as her is to get in their face.
her defense matrix i find to be amazing. you can shut out a ton of damage and move forward in a quick burst, unlike reinhardt's slow but safe shield push.
she is great at allowing her team to be aggressive and a well placed ultimate has the potential to win the game and/or open up a point.
even though i believe she is meant to be primarily offensive, i think that you can get away with playing her defensively on maps like hanamura where you have a lot of space to close off and pick targets.