"I Wish I Could Be Santa Claus" is a bit of a sad song on the surface (especially given its placement in LTS, when it looks like Gonzo won't get Claire's letter to Santa) but I have found it to be sincere and encouraging upon repeat listenings, especially in the re-release of A Green and Red Christmas.
It's a beautiful song that deserves its place among the Muppet classics, IMHO. I'm beyond grateful that Paul Williams is still writing incredible music for the Muppets after all this time.