Store exclusives don't seem like too much of an issue to me. There's a bit of added hassle in the same way there is for games with their own launcher/account system, but for the most part you're still able to get any game (and I believe even add it as an external game to your Steam library, if that's the UI you prefer) without significant cost/barrier to switching like there is for platform exclusives.
In exchange, it can add some much-needed competition on the developer side - with multiple stores competing to give a better deal. I don't think it's particuarly healthy to have pretty much just one store, sitting on a large cut and not doing much in the way of funding new games.
I do wish Epic would also improve in areas of Linux support/input binding/etc. though.
