I think the grand finals bans is way too strong of an advantage. I understand that it is necessary to have an upper advantage, but it can literally take a 4-3 series to a 3-1. I think the best way to do it is just removing the bans of the lower team.
Example: Right now it is
Ban - Ban - Pick - Pick - Pick - Pick - Pick
I think it should be
Ban - Pick - Pick - Ban - Pick - Pick - Pick
In this scenario, it still lets through the weakest map of the losers team, but I denies the current system of permaban + ban the best map the opponents. I think it adds more interesting impact upon the map picks, and lowers the INSANE advantage given to the winner seed. You can then select either your second weakest map or huge swing maps with the second ban.