I think some new ranks can be added, after GMG5 (GrandMaster Gold 5)
My idea is a prestige :
The players who are in top 10 of GMS (= GM gold 5) can do a prestige : They have a white but not under the player card but ON the player card, at the place of his mondial number
After prestige, the player is bronze 2 (like when a player starts, at 700 ranks) but he has the white star on his card.
It can let lots of player becoming GM and the GMG5 will be honored !