A Classic race at the TT would stop the complaints over the proffessional riders, but it would also almost certainly kill the classic races at the manx! As many of the top classic riders would want to compete at the blue riband event. In the same way that many top modern riders by pass the manx and go straight to the TT.
Surely preserving the classic race at the manx is more important!
Although they complain about them being there, I think a lot of classic riders enjoy the "name dropping" element of competing against the best road racers in the world, surely thats part of the excitment, it is for me!