I've found all of the MCU scores to be pretty generic, tbh, Avengers included, though it worked well-enough for the movie. Captain America: TFA's was good and perfect for that period setting, IM3 had a decent theme, and TWS had a score well-suited to it's tone, but that's about it. None of them deserve to go down in history with the best superhero work of Williams, Elfman or Zimmer, imo.
Honestly, the only recent superhero score of the last 10 years outside of Zimmer's TDK trilogy that I found to be anything remotely special was Horner's TASM score. But thanks to the overall mixed and tepid reaction to the movie it belonged to, I guess it's just gonna have to be one of those overlooked/forgotten gems.
TBH, I don't think Marvel Studios puts a lot of importance on scores. They are a notoriously frugal company, and I think the score is one of those areas where they are perfectly fine with cutting financial corners. The biggest composer they've gotten was Alan Silvestri, who is a pretty big get, but come on, they could afford the biggest names in the business if they wanted to. Instead, they tend to go for these cheaper, synth-based guys from the video game world. Which is fine - they generally produce good, serviceable scores that work well with their films - they just aren't getting any instant classic scores out of them.