As a huge Illini fan, I watched a ton of Big Ten b-ball during the regular season and really only thought there were 3 good teams there (OSU, Purdue, and Wisconsin). Then after Purdue's loss to Iowa and both their and Wisconsin's awful Big Ten Tourney performance I started coming around to thinking that OSU was the only really good team in the league.
So I'm not sure if it's a choke so much as just an overrated conference being exposed as overrated.