Improove Robin round
Add tool to create multi league tree. eg. 1st legue ,2 x 2nd , 4 x 3rd and 8 x 4th (i think 4 at the begining is enough) . Then add alghoritm for promotin and relegation. (Eg, 4 is relegated and 2 promoted from each level. or 2 relegated and 1 promoted or in case of same number of leagues on each level same number of relegated and promoted. )
I'd like to see a RR with two groupings where group A and B only play people from the opposite groups and not from within the group. It would be very useful for clan battles.