While rewatching Season 5 I noticed that there seemed to be a growing criticism of Barney running around with Juanita. To give an example in the episode Andy and Helen have their day Barney tells Andy to not repeat that he (Barney) and Juanita went to Morelli's for dinner to which Andy reprimands Barney for taking Juanita to Morelli's as it's one of the most popular places in town. To my knowledge there are only two instances in Seasons 1-4 where Barney got in trouble/reprimanded for dating Juanita: Barney and Thelma Lou PFFFTTT and an episode I can't remember the name of where Barney immediately hangs up on Juanita when Andy says Thelma Lou is coming over. Given how numerous it was in Season 5 (as well as how this season had Barney and Thelma Lou having a lot of relationship trouble), I do wonder if Juanita was going to finally appear on screen in Season 6 had Don Knotts decided not to leave. It would make for a good episode for Barney to have to finally choose between the two but given Bob Ross's (Not the painting guy) incompetence it would've probably turned out bad