i think you are right. there are fundamental problems with the gameplay that make Overwatch an unsatisfying esport to watch. mostly, the gameplay is too fast paced, and ultimate abilities are basically win conditions so a lot of "strategy" in pro games devolves into "charge up 6 ults, speed boost in and pop em all, hope it works out"
I think Blizzard would have to introduce massive, gameplay-altering changes to make Overwatch a more viable esport, and I just don't think they care enough to do that. It's clear that Blizzard as a business has focused on catering to casuals for a long time now.