Characters like Reaper, and Bastion get inherently more value shooting tanks and shields than other characters do because they are able to drain them fairly quickly, while I don’t think this is a huge issue overall for a lot of tanks, this issue is why “counter swapping” is such a hot topic with characters like Winston. (yes you can play Winston into mei, reaper, bastion and find success if you know what you are doing, but it isn’t going to be fun at all and is going to be even harder without a skilled or coordinated team) Your ability to enjoy a character and their play style shouldn’t be so drastically changed by people playing certain characters.

Giving bubble a small damage reduction for even a second or 2 would mean that bubble diving as Winston is still viable against comps with Bastion and Reaper. I don’t think it would make Winston extremely oppressive as it really is only useful against characters that pump out insane damage numbers. A Genji caught Winston bubble wasn’t going to break it either way no matter if it has reduced damage or not. And a whole team shooting it is still gonna break it fairly fast even with reduction. But Bastion isn’t going to solo destroy it as soon as it gets deployed

TLDR: Winston bubble takes less damage for a couple of seconds after deployment, making the ability more viable against high-damage single heros like bastion, while not making much of a difference against the characters bubble is already strong against.