My feelings on the matter as well. Part of the reason why I play D.va is I like protecting people with Defense Matrix. If I wanted to play a more offensive character, I'd play an offensive character. Not really looking foreword to these changes in the slightest.
Ah, well. I played D.va back when Defense Matrix was a cooldown rather than a channeled ability, and I'll probably continue playing her now, but it's to a point where I may need to consider switching to an actual Tank character if the team is really missing one, and that doesn't feel great. At least being able to shoot while flying matches with what her Meka has been show to do in cinematics now...and I suppose there's always playing her in HotS. I already kind of prefer how she plays there to Overwatch anyway...though I suppose it's only a matter of time before they decide to nerf her there as well. -_-