There are players with skills over 20, BB ruled out any possibility how to see them differently than legendary. If it has any impact on anything, nobody knows I guess.
Zajino: It is not that crazy idea nor it produces crazy salary with some skills. Of course it is a trade off as such a player lacks in other things (otherwise he leads his team to bankruptcy) and then depends whether it is bearable for you team. For some concepts of team play it can be sufficient/useful.
And one thing is to train such a player and another to buy him and play him to his best. Dont forget training is stuck when you are not login in for weeks, that players hit market even without theor owner selling them and that such a situation can repeat in a completely innocent way (i.e. not farming) too.