Sadly I do not support this idea from various reasons:

1. Will add extra knowledge needed. (The game should be kept as simple as possible if possible!)
2. In theory, if you would have a "fresh" 2 stars players and you will compare him with a "fresh" 3 stars players on a race to become a 4 stars players with 3 positions and Special Ability, the 2 stars players will win which is unrealistic.
3. These changes regarding the speed of training for 1* and 2* will literally not gonna have any impact on managers with a medium or low activity in-game.

I know you have good intentions but we do not live in a perfect world. We live in Top Eleven world and we must be aware of this all the time.

This idea in my opinion will make 1* and 2* players good for something only for those managers with tons of green packs or tokens, plus, regarding the manipulation, will still be possible just like now, with indeed a small improvement.