1.a contract system when you sign for a club you sign a 10 game contract this would give new players in teams to adjust to teammates and stop managers kicking out players after 1 game (to fight people who just want to mess up other peoples clubs you would need some sort of kick vote system where a certain amount of team members have to vote to kick people).
2. integrate a transfer system where you can buy real life players like messi ronaldo etc (same as ultimate team earn coins through matches) these players would fit in around pros
3. a season pass for pro clubs
4. when making a pro clubs team that team starts off with a pitch and as you earn coins from matches you can then invest in new stadium stands so you build your own stadium as you progress you open better stands maybe with add on's that earn your team coins this would open up endless possibilities of custom stadium builds
5. with the season pass you could earn extra unique stadium parts also at a certain level in the season pass there should be a reward of some sort of club house (early in season pass) when the team can get a clubhouse they can,like in other games you can watch other players in your session you could watch the match that your club is playing while you wait to join.
6. a training pitch in where team members can go and practice set plays,play 1v1 2v2 3v3 etc this should be included in season pass at certain level
7. as with anything money needs to be made so rather than charge a fee for the season pass make it free and have a shop where you can buy cards gold silver bronze for your club.