My point is that there is no point to fight against those multiaccounts cause the problem will still be there. I see what you are trying to do but all it would probably achieve is that those multiaccounts will keep their trainees so that they'd be NT eligible. There will still be players creating specialized players for NT- some will be cheaters, some will be real managers trying to create the best player they can. I am in fact training 2 of my own draftees. I try to make them the best i can, using a lvl 5 trainer and doing one position training. However, I can't be sure that I'll keep them till they get old. I'd like to but many things could happen that might force me to sell those guys. At the same time, there will be a farmteam somewhere that has trained exactly like i have that now has to sustain the salaries of a NT player cause he needs to keep him homegrown and his player will probably get to the NT before my guys.
One way or another, farmteams are here to stay. The players in NT might become more salary efficient and have well-rounded skills but nothing would change in the big plan. All your change could do is even up the level of national teams cause it will be easier to train NT players in micronations. Maybe that was your intention all along?
Japan would certainly be stronger, there are a few great managers in Japan that could make great players, either with their own team or a farm.
Your change will not eliminate cheaters, they'll merely have to adopt to the new rules.