One of the issues of the game is that it's too easy too stockpile great players, because they don't ask for enough money after their rookie contract.
In my league, one FA CB rated at 98 was signed for a first year salary around 15 Millions. That seems in line with is value in the game, pehaps a little cheap, but it was what he was able to obtain on the open market. Would his previous employer have decide to offer him a new contract, the player would have been signed for much less money.
So, why should a player accept an offer by his current employer way below his true value on the market ? At least, he should ask more than the average salaries of ,say, the 5 best paid recent FA at his position with comparable ratings. Players currently under contract should index their renegociation on their FA value in their league.
English is not my first language, so i hope this is clear for you ;)