Perhaps introducing player packs for Gold Balls or Recruiter Coins could be a fun new addition. Make it like in Fifa where for example for 5000 recruiter coins you can get a player pack of about 5 Players of all levels. Obviously have the chance to receive players of all levels. Would definitely add another dimension of players other than from the recruiting market.
They had something like this a while ago where you could get 3 players for gold coin