I was a big fan back then, however, I never got into the last season. They basically swapped out everyone I liked except Walter, who's character was changed too much for my liking, and I quit almost immediatly. Is there anything worthwhile in there? Now that I'm thinking about the show, I might go for a rewatch soon.
A lot of stuff came together in the last season. If you’re curious how it all ended it’s worth a watch. I can see not liking the major changes heading into it, but still felt worth watching for explaining some things that still weren’t resolved heading into that season.
Shows that explore the implausible run the risk of getting lost and becoming incoherent. Fringe definitely got into that problem, but managed to pull it together into an emotionally satisfying conclusion - while not all elements really made sense, it felt right.