Yeah, I can't figure out D.VA at all. I've seen some effective D.VA's, but I have no idea how to use her myself.
I'm not even entirely sure how to fight her properly. Occasionally her damage output seems way higher than I expect, but most of the time it seems way lower, so I'm always kinda second guessing things.
Her boost does ram damage if you hit people and knocks them back. The D.Va combo is surprisingly simple. Ram some fool, then cancel your boost and start blasting away, repeat indefinitely. Neatly, the cancel boost button and shoot main weapon buttons are the same button. Her shotguns basically do no damage at anything but literal ram distance.
That's pretty much it. That's how you play D.Va. Constantly reposition yourself, boost has a low cooldown. Defense matrix high sources of damage, but most of all, SAVE YOUR TEAMMATES FROM DEATH with defense matrix. They won't appreciate you for it, or really understand what happened, but you will, and that's all that matters. Feel free to get in the thick of shit and disrupt the other team harder than a winston main, cause you'll eject from your mech and you can run away like the little girl you really are, and the mech does not take long to recharge.
Then cry because your ult is pretty much useless. Ult the enemy spawn door if you're near the last objective, about the most use you can get out of it is being a worse mei ult that takes twice as long to charge.
I agree her crit-zone is pretty atrocious, to the point where point-blank duels with a soldier76 usually result in
soldier76 winning the 1v1, despite how your armor should mitigate his repeated small-ish ticks of damage. At close range he will get almost all crits and you're totally screwed. (soldier76 needs his health field to win though). It doesn't help that when D.Va fires she is basically standing still cause the movement penalty is so huge (like 75% or something).
I wouldn't be surprised if blizzard reduced her crit-zone to something reasonable. Hopefully they'll accompany it with some other buff, like changing the movement penalty, I personally want her shotguns to have a tighter spread so she can duke it out with smaller characters in the side-lines where D.Va already does best, it wouldn't be a straight damage buff, but it would make her more effective than she is now against smaller characters without making her more effective against tanks (cause her balance against other tanks is totally fine TBH).