Leadership/aggresion
Leadership should be obvious : the higher it is , the better the team synergy bonus ( teams should also get a synergy bonus based on how much they have played togheter). I also believe we should be able to select a team captain for each team to make use of his leadership bonus....or penalty if the leadership is low or close to 0. That being said , the other players should gain something for their leadership score as well. So this is what i suggest :
A team , with high leadership captain should get a bonus to their player's individual abilityy (so....a captain that will tell each player what to do , and capable to micromanage them to make the most of their abilities) ,while a team with all players (besides the captain) with high leadership , should also get a % increase in overall team synergy (the higher their leadership , the higher their ability to follow calls and play as a team)
If the team captain has low leadership , i believe the team synergy and ability should be affected as well , and having players incapable of following commands should also affect the team performance
As for aggresion : i also believe it shoud be a 2 bladed sword : for good players , a high aggresion should be rewarding , while for bad players it should be detrimental (playing aggro while being bad will result in feeding usually).
Again , i repeat myself , i dunno what the devs had in mind for said stats , but i feel that what i usggest is not a bad ideea.