Hate to break it to you but Players are leaving OW period, and the ones that do join are going to lean closer to DPS as their first picks in the hero pull.
Like their shooting on balancing the roles at the moment, And ya thats going scare away the people that want a power fantasy over a fair game.
Especially since OW was basically designed around everything being a broken tool or ability, to learn the hard way of balancing something like is almost impossible when the power curve is all over the place.
Now that just about ever tool is being pulled closer together, Sigma with all his tools and utility gets the clunk that comes with being so multi-purpose. While the heroes that have more clear cut specific playstyles are having a bit of their reins loosen.
Like winston the hero that can jump and place a bubble, is still usable in an environment were a hero packed with stun, shields, DM, decent damage output, and a team wipe ultimate, exists.