Personally I am a firm supporter of the 6 lap races. Don't forget that the TT should be a test of endurance as well as sheer speed and handling skills. It is also a test of the bikes, the designs and technology of which find their way onto the bikes we ride on the road.
If the 4 lap races become mandatory and therefore outside "our" control, then the winners should not be seen as lesser mortals compared with the Heros of the past.
I am not in favour of "disposable bikes" that can manage only 4 laps.
It has been said before, probably on this site, that the winner of a 400metre race can be just as exhausted as the winner of a marathon race.
A modern bike can be "Easier" to ride than one of the pre-disc brake, pre-trick suspention era. I know this as I ride bikes from 1999 back to 1919.
My 1999 Super Blackbird is a lot easier than my 1977 GL1000 Goldwing, even though the Blackbird has twice the engine power.