I’m not sure if I have read all your messages or miss read, them but I apologise if I have.
I think your idea would only be countered with Zwifters changing their gear set up.
If a Zwifter wanted to use a cadence of 95 as opposed to 65 to achieve the required 350 watts there is no way that Zwift or anyone can stop them.
All they would do would make the appropriate gear configurations, possibly even using a triple on the front, or custom making their own rear block and eventually differing blocks.
The really keen Zwifter racer, (not me) would eventually, if the put their mind to it know every gear setup for every Zwift race circuit and be happy to change their setup to get the win or placing.
The Zwift slider just means that ant Zwifter whatever there setup can have a usable set of gears to enjoy Zwift.
I totally get that many Zwifters want total realism, even more so on the racing side but in all honesty I feel it just won’t happen. (not that I can see)
I thought I had a great idea when I started Zwift racing. A Zwifter would go to their LBS to be weighed, height checked, power checked? gender checked LOL
but in reality it’s not going to happen.
The a biggest part of the problem I think is that the whole race system is weight based, which bears no reflection on real life, this is what need changing first in my mind.
Sorry to go on.