One Idéa I've always wanted to see in a magament game is something I'd like to call a "shirt seller". This is something not so unusual in IRL sports. A player that isn't nessesary skilled but still represents value in other situations for the club (Think Beckham, Magic Johnson or Bob Sunesson in HT).
Exactly how this should be implemented if this idea is intresting is a little early to say (for me), but I'd like to present the idea to be dismissed or acted upon.