I don't like it. It strikes me as a score nanny issue with the idea that so-n-so is getting their score with easy to fly planes, therefore we should take them down a peg. But the same planeset is availible to all during the course of a tour, so it is a level playing field whether someone chooses to take advantage of it or not.
Availible time to play is not a level playing field for everyone, which is why accumulating "points" is only 1/5th of fighter rank, and is a great feature in that regard.
I view plane diversity as more of a window dressing issue rather than something at the core of good gameplay.
Just my personal take on it.
I have made a suggestion in the past with a modifier for "points vs enemy", but it was directed at discouraging hording
vs enemy proxy modifier