How you feel about valk is fine. We can’t say that you are wrong in feeling that valk is impactful. It’s just for me and others we don’t feel the same rush as we did with mercy 1.0. I think the OP really hit the nail on the head by calling her the ultimate sidekick in a game full of heroes.
Yes not all mercy players feel that way, but as individuals we will always act in our own best interest and that means that we will voice our opinions because otherwise there will be no hope for a change to make her feel more fun again.