I think the issue is team play. Team play, for all its unique contribution to the fun of the game, also tends to level players up (too?) fast. For example:
I love tank play. It's more challenging than some would think, but easy enough to still be enjoyable while serving a purpose on a team. That's pretty much gone, or at least seems to be to me lately. The tank should be grabbing the aggro to protect the rest of the team, for example, but on so many high level runs lately, I find myself stuck behind seventeen robots, demons, or somesuch nonsense, basically placing me in cleanup, while my teammates in front either die on the regular, or rush through the mission. I might as well be doorwatching.
I enjoy and appreciate my power levels for soloing some content, but I love this game for its teamwork aspect. A good team is hard to find, but an amazing experience.
Could there be a way to balance team construction, so that you literally have to piece together a perfect combination? Not sure. I certainly don't think the game needs to be "fixed". Those times I luck into the perfect team are why I play the game. The rest is drudgery.