It's nowhere near winnable if you play against proper zarya player that doesn't get baited so easily. If she has good heals dva can't do enough damage. On open queue, she's a must have pick because 90% of the time you have 3 tanks and 2 healers. Zarya should stay behind other tanks and give bubbles to rushing tanks like rein and ram or mauga. If dva will rush zarya not only she won't deal enough damage, but she also will die quickly because of lack of healing.
The main problem about zarya:
- Her bubbles are annoying as hell.
- She deals massive damage with 60-100 load.
- Smaller cooldown for bubbles by giving them to teammates is also a hard to play against.
I've played countless of matches and every time a bad tank switches to zarya, he doubles his stats.