Okay, I realize these are gimmicky ideas, but in case any of the show's creative people are reading (hey, you never know), here are just a few ideas I had that I think would be funny.
1. Show Within the Show. Since they occasionally all watch TV together, have them tune into a "new show" called, "Friendship," with six characters that are nearly identical versions of themselves, all played by the same six actors. Think "Russ," but with versions of all six of them.
I'm thinking there could be two kinds of jokes. One, just as Ross didn't recognize his own qualities in "Russ," they can each criticize the characters for the same flaws they share. Know what I mean?
Second, they could make comments that satirize "Friends," for example: "Yeah, like these people could really afford that size apartment," or, "Sure, like everyone's roommates just happen to be so attractive."
Okay, maybe it doesn't sound all that great, but I think it might be funny.
2. For some reason, just because they occasionally make reference to "Three's Company," I think they should get some of the original "Three's Company" actors to do guest appearances or quick cameos, maybe even as their original characters. I especially think Norman Fell and Audra Lindley (sp?) as the Ropers (or if necessary for legal reasons, maybe just an unnamed couple that act exactly like the Ropers) would be great to see. (Having recently seen part of an E! True Hollywood Story on "Three's Company," I gather that John Ritter, Suzanne Somers and Joyce DeWitt aren't exactly too fond of each other, but the Ropers would be just as good, if not better. Don Knotts might be fun, too.)
3. I think I already said this, but I'll repeat it anyway. Especially if this is going to be the last season, I think it would be fun to bring back, just for quick cameos, as many of the memorable old minor characters as possible -- maybe even all in the same episode. Like all the old boyfriends and girlfriends, etc. (I personally would like to see that psychologist guy Phoebe dated -- the one that irritated the hell out of them all by analyzing them -- reappear and comment on Chandler and Monica's marriage, Ross and Rachel's relationship, etc.)
4. Gunther deserves a love interest. Just a minor thing. Not one of the regulars. Maybe, dare I say . . . Janice? :-)
Dave