I don't think its necessarily superhero movie fatigue but hype fatigue.
They're hyped so much and it's getting earlier and earlier with movies being announced years in advance
That is what is irritating me about the whole thing. Stop ****ing putting release dates on sequels before the current film is even ****ing out! The announcement of Avengers 3 & 4 has in fact dulled my excitement for Avengers 2 since it is clear before I even see the damn thing that Ultron is small fries.
Also, I can't help but think about what age I'm gonna be when these sequels arrive in 20 ****ing 20, or what age my older brother or my mum & dad are going to be. So please ****ing stop. There's really no need for us to know.