I like the question more in terms of a true re-union, since the objective of the thread was to compare before and after music. Can the same people do better work after they broke up their band?
Without making that distinction, then post-Stormwatch Jethro Tull is also a candidate, since Ian Anderson has said that the band was actually defunct at that point. Everybody from the previous band was either fired or dead, save for Martin Barre, and IA had plans to do a solo album.
Somehow though, Ian Anderson, Martin Barre, Mark Craney, Dave Pegg and Eddie Jobson doesn't strike me as an example of Jethro Tull re-uniting...