I want to have a player that has been trained by me for a new position to STICK forever to it because this really happens in real life.
I do this to EVERY single player I manage... ALL, i mean absolutely ALL of them (except GKs), learn a new position that fits into my formation.... but when I sell them or leave the club, the new manager changes the schedule and they "forget" that position. In some cases it makes a bit of sense, p.e.: If a player only has trained in that position and hasn't played more then a few games in it... it really does make sense that he forgets it...
...BUT, and here is a great argument for me, if a player learns a new position and plays at least one entire season in it, does it make sense that he forgets it? Even considering the versatility stats. I've watched lot's of players in real life change the position they occupy in the pitch along the years from hard work and/or persistence.
Examples:
FÁBIO COENTRÃO from AML to D/WBL . . . he is now an absolutely fantastic player who can occupy any position in the left flank.
MIGUEL - was a good AMR on Estrela da Amadora and when on to become a world-class D/WB R.
PIRLO - started as an attacking midfielder early in his carrer and when on to become one of the greatest DMC ever!
BALLACK - was also an AMC for most of his career but in the late stages of it, he could occupy more defensive positions in the midfield.
GABRIEL HEINZE - started as a left-back and is now an excellent center-back.
CHRISTIAN ZIEGE - look for info on him and you'll see the position changes he had along his career.
LUIS ENRIQUE - should i say anything?
and i could go on for days.
All of this just to say, if a coach finds himself in one clube with a player who has been occupying and performing very well in the position of AML but is originally a CB, would he discard the player's ability to play in one of the two positions?
This change could even become permanent in more or less time, depending on player's mental stats, versatility and what not. AND maybe... just maybe, should he be playing for 5 ou 6 seasons in a row as a natural in a new position he has learned, maybe he could become unnatural in the original position just a little bit or even forget it if the FM programmers think they should stick to this feature of "forgetting".
Finally, of course it shouldn't be as simple as training, reaching a natural status in a position and stick to it FOREVER, that you I would put IBRAHIMOVIC training as a center-back in his 32/33 years and buy a new SC and have for more 2 or 3 year an absolutely amazing IBRAHIMOVIC as a CB and a shiny new wonderkid striker. Also maybe after a certain age and considering once again a lot of attributes, some players wouldn't be able to learn new positions or wouldn't be keen to do it or should learn it in a slightly bigger curve that younger ones.
Sorry for the HUGE post but if it is to give ideas, I try to give them as detailed as possible.
Regards!!!