I recently purchased the complete series and I began watching episodes from Season 5. The opening episode Suicide Stunt is really bad~ bad script, bad acting etc.

I also noticed that there was tension between the actors. Even Robert Pine appeared to be agitated and no I don't think it was meant to be directed as such. I think the rift between Estrada and Wilcox was so bad that most of the episodes had to be rewritten to have only a few scenes together. I think that's why Bruce Jenner was brought in as well.

Oh sure, there's still plenty of Jon and Ponch, but there seems to be more scenes of Ponch by himself and Ponch interacting with other cast members. Since Larry was the one who was unhappy and ultimately left the show, they gradually reduced Jon's time in each episode.