For me the rot set in when Associations was introduced. The overwhelming disparity between the prizes on offer for the Association both in weekly competition and the monthly top 100 table, etc., and the ordinary game (League, etc.) was just asking for any and every loophole in the game to be exploited by the inventive and the unscrupulous.
Every change since then has been to try to close the loopholes, fix the problems and counter the effects. Unfortunately, the ultimate effect has been to distort the original game, to the detriment of the player who wants to see his team do well in the conventional competitions.
To me the ultimate solution is to remove Associations for a time, get the core game back on an even keel, then reintroduce Associations or something similar with a revised prize structure. It wouldn't hurt to revise the prize structure for the league, Cup and Champions/Super League as well, to reduce the difference between the two sets of competitions and the temptations to 'screw the system'.
Associations was a nice idea, but ultimately poorly implemented.