I was heartily sick of it and I think it dragging on killed the ratings in S4. I am not discounting the effect of Taraji leaving had but taking that in to account I really think that it went on way too long. YMMV.
shareI lost a little interest in POI after season 3 as well. I watched the rest, but did not really enjoy many of the episodes in season 4-5 as I did when Carter was there. The show took a few turns that obviously alienated some people. Yet some other people liked the turns. Samaritan v. The Machine seemed to drag on too much with so many redundant gun fights that looked comical after a while.
Loved the whole Elias part. Dominic was okay too. Shooting the bad people at the kneecaps just wasn't as satisfying for me after a while.