Unless I'm missing something, this doesn't sound any different to the learning speed hidden... Having something like this in parallel to learning speeds feels like an unnecessary shortcut to artificially level some relatively non-existent playing fields. I would get 0 satisfaction from getting a fighter with high professionalism hidden and cutting to the top of the P2P as a result; that's one way to quickly tire the game out and make it boring for all involved.
There's a fine balance when it comes to these things, one of which being the learning speed hidden - it already provides new and old players an equal playing field so long as you're playing within your ID range when starting - if you look at the Island as an example, old and new managers have a level playing field where they all go against each other with relatively similar fighter stat distributions.
If the intent with this was for the new boy on the block billy KO'ing the top P4P fighters because of his turbo-charged Professionalism then unfortunately the intent is misdirected. I like the creativity that comes with the suggestion though so I appreciate you taking your time to put this together as it helps us think about another dimension to an already solid system.
Unfortunately, we won't be progressing with this suggestion so therefore it's denied. Hope you're not discouraged from suggestion more of your ideas in the future!