What we know so far:

You people REALLY want to see Baptiste and Mei changed (number of responses: Mei in first place with 16.8%, Baptiste in second 15.3%)

Third, Fourth, and Fith respectively are Hanzo (10.3%), Orisa (7%) and Sigma (6.4%)

The abilities You want to see changed the most:

Mei: Primary Fire

Baptiste: Immortality Field

Hanzo: Storm Arrows

Orisa: Fortify (though just barely ahead of Halt! by 2%

Sigma: Experimental Barrier

by FAR the biggest suggestion is regarding Mei's primary, and is a toss-up between removing it's piercing/multi-freeze effect, and nerfing it's slowing effect during/after being hit by it.