I'm not understanding what there is to be mad about. Between 1992 and 2010, most Marvel series made either capped off somewhere between 13 and 26 episodes. Heck, this was even a thing in the 80s when the big hit series only clocked in at 24 episodes. Marvel series are consistently going longer now than they ever have. 52 episodes is seriously nothing to slouch at and I'd take that over watching a series go so long that it becomes fatigued. I could have done with more AEMH or even a true spinoff series like so many of the longer running action series get but 52 episodes is still a lot to enjoy (whether you like all 52 or not). I'm really happy that 52 has at least become the new average for episode count. If anything I'd just hope for a higher average of quality with the numerous series.
"I've had the same car since I was 19 years old, and never had a problem, yet this thing falls out of the sky every other Thursday." - Maria Hill