I'm with ya. While season 5 had some phenomenal individual scenes (like "tread lightly"), it didn't land with me as a whole in the way the earlier seasons did. The finale of season 4 is to me, with the haunting "I won" line, is the ultimate ending in my mind.
100% The first four seasons were great, with a ton of character development. The last season was incredibly rushed, and felt like they went from $0 to $millions overnight, and then introduced (annoying) characters and fell into quick traps. It was super frustrating to me.
I actually thought BB went downhill and quit mid-way through the last season, but I understand I'm in the minority.