I thought it also could be a 1 on 1 style format with a ranking system so it would be more like boxing,mma,or wrastlin. Where you could have a tournament to start with,and allow anybody to participate that wanted to. Then the winner of the tournament would be your leagues "champion" and players would have to move up the rankings to be able to challenge for the championship.
The problem I had with that format is how to set up and implement a ranking system. Like how do you decide who is what rank to start out with? maybe try and get 50 ppl for the tournament and the top 20 or so get the league guild tag with a rank attached to it. Then as ppl leave recruit more for ppl for the league,or once a week get ppl to join but the have to beat the lowest ranked person to get ranked. You could use a sub guild for ppl who have joined but aren't yet ranked.
I also thought it would be nice to have the spar matches in gh's that way you could mix things up with different spar match types. You would have to set up fences in a square shape for the spar area. Then you could make it so they are only supposed to attack with arrows or bombs instead of swords. You could even have spar match where each player are on mounts. This would also let you vary the # of spars in a match. For example you could have 3 ppl sparring each other at the same time a Triple threat spar match.
Or if you really wanted to you could design different looking spar areas. Add obsticles,vases to throw,have a statue with the current champ on it,ect.