You also have to be a pretty damned old-school Marvel reader to know Thunderball's supposed to be smart. The last time I remember him being depicted as such, as opposed to being the smart guy on the Wrecking Crew, was in McDuffie's Damage Control limited series from the late eighties.
Since then, the Wrecking Crew have been pretty strictly B-list. Thunderball wasn't even particularly smart in Secret Wars, which may have been their highest-profile appearance.