Cap Hydra was a fascinating idea that required a much better writing team to execute it -- and Marvel obviously got cold feet halfway through, so the whole thing ended up a mess.
I could see it working as a non-Marvel-branded novel or movie, for instance.
That said, doing Cap Hydra now would have some interesting resonance, although that might make Marvel even more scared of committing to it.
But the winner is all the garbage they've been doing to Spider-Man since the early 1990s. Once Marvel got the whiff of the money to be made with stupid events and gimmicks, Spidey in particular has never stopped having them. The Clone Saga was terrible, but so is Iron Spider and millionaire Peter Parker and One More Day and weird inter-dimensional villains hunting Spider-People for nebulous magical nonsense and everyone in NYC turning into spider-people, etc.
At some point, Marvel is going to realize that the audience for the Friendly Neighborhood Spider-Man has been replaced by the "what fresh hell can we put Peter through today" audience and not know how to fix the brand.
More generally, smashing the status quo for the sake of a stunt rarely works. Everyone should stop doing it, if they want their brand to retain its value. (This especially includes "what is Superman ... BUT EVIL?!" We've seen it. Enough already, edgelords.)