I'm not an SAO fan, but I get why it's popular. It appeals to a teenage demographic the same way that Michael Bay movies do. Lots of fanservice and action, little thought goes into the story. It plays out like one of those fantasy things you might do when you're younger with your toys and whatnot.
It's essentially like a fanfiction written by a teenage boy. As much as it fails on every level at connecting emotions, I can have some level of respect for it because I don't honestly believe it ever intended to be anything except wish fulfilment. As far as I understand, it was a secondary project by the writer who made it anyway.
One thing I don't get is why people like Aincrad so much. I'd call it the worst part of the show, honestly. It has the most plot holes, it's the laziest at storytelling, it wastes the premise and a potentially good villain, and half of it or more is filler that borders on harem stuff.
I... don't know why AoT is popular, though. I've never actually seen anybody, not even fans, contest that the show has poor characterization and pacing. The script is among the worst I've ever seen. With how much dialogue there is, I'd assume that target audience would just get bored of it. I mean, nothing actually happens in the show. If I were to spoil everything about AoT in this post, it'd kinda be like me saying "btw White Walkers are in the prologue of Game of Thrones."
I'd love a perspective on this, actually.