While the obvious choices would be to enhance the bonus/extend duration, what would be cool would be any roll that is at 11 should not be counted as one of the "2 rolls" you have. Meaning if you had 2 rolls up, and one was 11, you could be able to do a third roll (on anyone that already has 2 buffs with one being 11).
This should probably be limited to 3 or 4 buffs max or else it'll just get silly.