There are a few things I noticed about this season when watching the set.
One, it seems that many of the introductions for the opening numbers this year are a bit long, often with interruptions Think about it - Miss Piggy comes out from behind the curtain to tell Kermit what her number with Kris Kristofferson is, Leslie Ann Warren comes on-stage to settle some confusion, Raquel Welch's openign number is delayed by interruptions by both Miss Piggy and Scooter, Fozzie interrupts the intro to Roy Clark's opening number, Fozzie interrupts one introduction to make a joke regarding Jean Stapleton's name... A lot of long interruptions before the opening numbers.
Two, I noticed that scene transitions are less common this season. The previous seasosn had a lot of transitions, even during introductions (where it was not uncommon for Kermit or whoever to make an introduction and then, instead of raising the curtains, the frame slid to the side or somethign like that). This season still has the occassional transitions, usually just fading, but for the most cut scenes usually cut to the enxt scene and the curtaisn always raise during introductions.
Three, it seems like some characters appear less this year, even though they had somewhat major roles (in one case just being important enough to have his name in the credits) in The Muppet Movie. I am referring to Dr. Teeth, Sweetums, and Crazy Harry (the last one being the one I'm referring to whow as important enough to be credited). they all appeared a lot in the previous two seasons (Crazy Harry wasn't really there that much in the first two, but his number of appearances in both of the first two seasons were almost equal, while this season it's just two or three). And looking at their Muppet Wiki filmographies they continue to appear less throughout the series (though I think Dr. Teeth makes more appearances in the next two seasons). Dr. Teeth is hardly ever seen this year, and when he is, mit's usually a non-speaking background performance. He only has line sin three episodes, two of which are UK spots.
Four, and this is related to the last thing, is that The Electric Mayhem doesn't make many appearances as a group. Floyd, Animal, Janice, and Zoot are all seen alot, though often only one or two appear at a time. Janice is often seen in Veterinarian's Hospital, but rarely seen as a musician this season. The episode has quite a few numbers where te orhcestra performs, but Dr. Teeth and Jancie aren't part of the orchestra. The first two opening numbers feature the band providing back-up, but they arn't too noticiable in those numbers (unlike earlier numbers where they provided back-up, like Lou Rawls' "You're the One" and Elton John's numbers).