The 22nd amendment could be readded...with term limits for all the politicians in DC.
Wiping the slate clean would get rid of so many of the failed (14th, 20th), downright un-American amendments (16th, 17th, 23rd) and useless amendments (18, 21). Also gets us a chance to have a vote free of the Edith Wilson allegations for the 19th amendment. Altering the 26th and 24th amendments could take us back to the pre-Jackson system where you had to have "skin in the game" in order to vote, where no idiot who promised free stuff could waltz into office c/o idiots who don't live in the real world believing his hype.