montitech: I dunno...Cheese's behaviour is defintiely very toddler-like, but to compare them too closely doesn't give toddlers enough credit, or gives Cheese too much. Sure, little kids often act impulsive, crazy, loud and demanding, but you always feel that what they're doing stems from a spark of intelligence, and that they do have a real persoanlity and internalised worldview, no matter how primitive and nonsensical it might be. I wouldn't say that the same was true of Cheese, to be honest; he doesn't seem to have any thought processes at all, instead running around doing things in a manic, instinctive yet fundamentally braindead way. I guess one could describe that as a personality (in the same way you might say black is a colour, or zero is a number), but you could hardly say it was one with any level of depth...
I've got to disagree with your analysis of Goo and Coco, too, actually, because I find that both of them are a lot more nuanced than people give them credit for. Goo, in particular, is a character who I really feel has tangibly developed over the course of the series; at first glance, she does indeed seem to be the archetypal hyperactive nutjob, perpetually swept up in her own stream of consciousness and oblivious of the world around her, but over the course of "Go Goo Go" she gradually came to reveal her hidden insecurities, the fact that she
knows she's a kook and the way she uses her hyperactive imagination to compensate for her loneliness. Since being accepted by the Foster's crew at the end of that episode, however, she's really progressed a lot; with friends surrounding her now, she's learning how to channel her imaginative energies into productive outlets (her work as an unofficial liason officer/organiser for the house), and indeed has developed a lot of pride in herself and her talents (the way she comes to the rescue in "The Big Cheese", or her obsession with winning in "Make Believe It Or Not"). That's an actual character arc, and
Foster's doesn't normally do many of those, so I'm impressed.
Coco's trickier, because as you say, she's never really had a dedicated spotlight episode; the closest she's come to one was "My So-Called Wife", which saw her acting in an uncharacteristically lunatic, illogical and, dare I say, Cheese-like way. That's misleading, because from her supporting roles in other episodes the impression I get of Coco's personality is a lot more textured; in fact, I frequently feel that she might actually be the smartest and most mature of the central friends. She's certainly headstrong and emotional, the one quickest to anger when crossed and quickest to seek retribution (see "Cuckoo For Coco Cards" and "Crime After Crime"), thanks to a slightly sly and devious side, but she's also got a maternal nature ("Who Let The Dogs In?", "Good Wilt Hunting") and can be a little sensitive too ("Cuckoo For Coco Cards" again, but also "The Big Picture"). Sure, sometimes she just acts nuts, and sometimes her egg-laying can be used as a bit of a
deus ex machina plot device, but I still think she's actually a deceptively rounded character.
Back on topic, though, I've recently rewatched most of the series again, and I agree that a second viewing can do a lot to your perception of an episode; it really cemented my views on a lot of classics (the likes of "Bus The Two Of Us", "Room With A Feud" and "Frankie My Dear" just don't get old) and gave me renewed appreciation of a lot of ones I'd overlooked ("Neighbor Pains", "The Big Picture" and "Go Goo Go" are now amongst my favourites, whilst "Hiccy Burp", "The Big Cheese" and "Land of the Flea" are
much better than I remembered). Still, there were a few that still didn't really click with me even after a second viewing, and "Cheese A Go-Go" was one of them (as well as "Partying Is Such Sweet Soiree" and "One False Movie"). There are some funny bits there, but I still just find it too fast, too manic and too plotless...