A big deal I see with comics isn't necessarily the gore or the length (though they turn me off, personally), but that the stories aren't really "about" anything anymore.
I mean, it used to be that Batman stories were (in general) detective or crime stories that happened to star Batman. Starting in the late '70s, it seems to me that the stories became increasingly just exposition of how much X Batman is in comparison to Y. Is Batman stronger than the Joker? Is he better than Ra's al Ghul at competitive eating?
If I wanted to spend my days looking at illustrated but meaningless statistics, I'd collect baseball cards.
When Roy Thomas introduced the world to Retroactive Continuity, comics became even more painfully self-interested, even though I think Thomas got it right. They started telling extensive stories about the early days, retelling the (ack!) origins, and fleshing out exactly what was in that sandwich that Cyclops ate in that one issue.
Continuity is great, but you don't tell stories about continuity any more than the list of Egyptian Dynasties or the make and model of Chekhov's infamous gun is a compelling tale. Continuity is the stage. You set the story in, on, or around it.
That's the worst part of reboots. Rather than hit the ground running and excite us over the potential of characters and their world, every single writer feels the need to slowly and carefully introduce his cast of characters and make sure we know why everybody is where they are, and we never get to the actual story before falling asleep. I've said it many times before, but never lead with an origin in anything more than a thumbnail; anything we need to know can be explained as--get this--part of the story, even if it's a flashback.
Because the other extreme stinks, too, and that shows up from time to time: The writer that just draws content from obscure sources and thinks his story "follows naturally" from what he thinks he remembers reading in that one book, so there's no reason to actually explain anything.
Hm. Here's the scariest thing you're going to hear today. "I'm going to cut this short." If you think about one end of a beast swallowing the other, you'll realize that there are two ways such a thing could happen. I'll leave it as an exercise to the reader which one makes more sense in the context of comics.
