Yes, you are right, that would be the best approach, both for the us and Nordeus.
It is true not many users keep the players for sentimental value or their hidden quality - I mean by that players that despite their lower skills and star quality, perform exceptionally. Many of the managers just go for a new, higher avg player, so tokens are spend regardless.
But there are quite a few of these retirement rules requests already and I don't see it as something that hard to implement.