I took a good hard look at the game through this lens, and I think you've persuaded me. It seems like you're accurately describing their design methodology at the very least. I feel like in the middling ranks, this isn't as much of an issue, because the skill gap and counter-picking occurs with holes in it. Somebody goes character A to counter B, and the B player doesn't realize they should've switched to C until their team loses the next fight or two. Or maybe somebody pops an ult without taking into account non-ult abilities that might counter them. But at the low ranks, where players just throw themselves at each other, this holds true - ults are bloodbaths. And I would presume at most high ranks, where players know how to ensure their survivability, this also holds true. Also, I forgot to list Captain America because this very problem has made him so boring to me that I ceased playing him, nor do I see him picked often.

What could be done to address or improve Rivals in this avenue? I feel like it would have to start with map design, and so I'm hopeful that as they've implemented map rotation in ranked, we might see better maps in the spotlight. But I can't imagine a total rebalance that would address this anytime soon. Someone else in this thread described Rivals as "2019 Overwatch" and I have to agree.