I have 3 suggestions:

1) Allow more formations, which are illegal at the moment (so it will become more realistic) eg play with no ST (or put him in an AMC position, play with 2 DCs, etc (many top teams play with no classic ST, yet this is illegal on Top Eleven, or some teams play 4-4-2 with fullbacks at DML/DMR and with 2 DCs, which is still illegal in Top Eleven, etc). I don't understand why if you play a 4-6-0 with red arrows on 4 players at mid,you loose all ball possession. Roma played a 4-6-0 (or 4-5-1-0) with great success at 2007, even Barca some times doesn't use a classic forward and many teams followed since then. And still, is illegal at Top Eleven. Really don't get it.

2) Put player tactics alongside team tactics (so we can give orders to certain players for man mark, be more aggressive/defensive, etc). eg sometimes I need to play with libero who will man mark alongside team's zonal marking and I can't.

3) Make much more costly and time consuming the investment in U21 (asset value: several millions just like stadium, instead of some K) but reward managers who choose to invest with more/ better players than these 2*-3* (eg let the manager choose 2 or more players from a list of 5 or more, or to order in which position does he want the next youth players at the start of the season, etc).
I don't get it. I have 50 millions at my balance sheet and I really want to invest some M on my youth but I can't. I don't want 100% foreigners at the team.
Also, I had 3 consecutive times GKs from my youth as the better player. I guess it's a random choice but, 3 GKs at 3 times? Really?What a great goalkeeping coach..!
Btw, the free player, 2*? He's not an average player, he's a bad player with no future to get better or to help. Only the good one has the chance to improve and contribute to the team.
Make us pay more for U21 and award us more as well.