my fave FF games are 7,8,11, and tatics. if you roll them all into one thats what i would add

1. Armor and weapons from FF7
2. Card game from FF8
3. Party system from FF11
4. Jobs from tatics
5. Summons were ok in 11 but i would go with 7 or 8
6. No sphere grid if anything, ap like in 7
7. Personal Air Ships like in 7 or 8
8. AH like in 11
9. Chocobo catching like in 7 then start breading like in 11
10. Limit Break like in 7


i could go on forever but i think you get the point.