In my opinion GKO don't need this changes. The "problem" of the training is for all the managers, I don't see the problem. If admin changes the possibility of progress all the players of all the managers will increase their abilitys, and the difference with "bad" players will increase.
Yes and no:
If you leave a fully developed player training "Attacking" it's 99% sure that your player will increase passing, crossing, off the ball or creativity. So if an attacker keep that training set he will surely improve something useful.
But what happens if you set "tactical"? The chance to improve decisions or teamwork is really low (outcome is far random than other training schedules), so people never had the chance to adapt themselves to the new engine.
In fact, the last time that admin said something about the new engine, he said that teamwork would provide "bonuses", i am not that sure that things are exactly like that: need more testing, but i have many clues proving that teamwork is now used in all team tactics, but it's not a bonus booster, it's part of every single formula!!!! I have a DC who used to have A+ in UZM, now he's got C+, a morale drop is not enough to justify such drastical change. That player's tw is 6, i never played offside trap and i didn't need a 'bonus" (as admin pointed that tw was meant to) so i never cared to improve it. I have the feeling that actually, those players with TW lower than 10 dropped their tactical skills, those with TW at 10 remains the same and those with TW higher than 10 increased their tactical ability.
I understand that all players would increase at similar rate, but i also know that fully developed players are now in a big dissadvantage compared with players in development.