Ghost Protocal and Fallout are absolutely great movies. Rogue Nation is better than 3 too. I rewatched them all last year and I had a blast with it.
The most recent movie, was a step down for me. Maybe because it didn't conclude, I don't know exactly. I think the two part thing they did was a poor idea, I don't even remember what happened.
But I have noticed that I tend to enjoy these MI movies more on a second watch. If you haven't rewatched 4, 5, and 6 i think it's worth revisiting. I also had the same opinion and when I went back to them I really gained alot more appreciation for the series.