I think they should all do it.... as long as they arent required to act like young guys anymore.... They should play "old" people... they are all still great actors and actresses... and masters of the craft (but dont cast them just for the sake of casting is what I hope)
You know, cast the old crew to stand around and act like older more refined/sophisticated versions of themselves type thing.... then I say Heck Yes!!!
(offtopic) They had a batman where robin wore batmans suit because bruce wayne is an old man so he cant do that crimefighting type stuff anymore... it played off the dynamic of being an old retired ex- "super guy", dealing with aging and just issues with being old, while at the same time stepping into the wise mentoring role... Its a neat area to explore for the writers as well