I'm currently at 77% completion and so far I feel Jeff's 4 stars is a little too generous... I might have burned myself out by doing the side-quests too early, I dunno. I like the powers and stuff, but overall it just feels like I'm going through the motions and occasionally getting some funny content to keep me from losing interest. Maybe it picks up in the last few hours, we'll see.
I think you played the game poorly like I did. I had all the side stuff done, and was at level 52 well before the ending. The game does drag a lot by doing that, but it does make the actual missions stand out more.
Still, it was a terrible decision to play that way. I just hated seeing that my quest-log constantly had 9 missions in it
I would clear out my side missions before progressing with the story, I hit max level somewhere around The Kinzie Gambit, cleaned up all of the collectibles before the final mission, but it seems I had an entirely different experience to you guys. I found that the activities were generally really short so I'd bang through a character's side missions and then have a big chunk of story content from a loyalty mission followed by a main campaign mission, which seems like a good ratio of repeatable missions to bespoke content.