The quick fix is NOT boring. It is a more dynamic way to play the game.
The heavy and sniper classes ARE boring. They are a less dynamic way to play the game.
We are arguing about balance in a game with NINE different classes. This has always been a game of rock, paper, scissors. The beauty of TF2 has always been how so many different play-styles can interact in a single FPS game, forcing players to react to different situations.
Banning the quick fix makes 6v6 more about following the rules of advantages and less about competitors adapting to and overcoming their opponent's play.