I think something that would help is some way to automate it across multiple games at once which would let us have a lot more people join in and therefor more variety in users. While we only have a handful of participants for the tournaments this isn't dictated by entries anymore but time.
Suggestion
One thing I would love to be able to do is have a qualifier round that lasts over a week or so. Players interested in joining the tournament would go up to the multiplayer menu and swap over to a tournaments server(or maybe there's a big button to do it) where all the rules would be explained as well as other info such as date and time. From that menu players can battle other people all week and be ranked based on performance (probably wins?). All the battles would follow the same rules as the tournament (or maybe a little different). Then after the qualifier time is up we take the top 16-24 ranked people and hold the tournament as normal with them. If someone drops out we can just pull whoever was next in the list. This could also be made for anyone to use and set up so they can host their own tournaments.
Problems with this
Problem: We really couldn't livestream the qualifiers this way. I know I wouldn't care about that personally but some people would want it.
Solution: Open up the battles to spectators and remove spectators from the lobby count. Of course that would probably cause lots of server issues when lots of people try to spectate. Another solution would be to have the server record the battles and upload them in batches every day.
Problem: People could just lose on purpose to boost their friends rank.
Solution: Only let players battle each other once. The functionality to know which client is which is already there through the block system so this could piggyback off of that.
Problem: Server lag and desyncs
Solution: Don't count the battle for either player. No one should be punished or rewarded for bad connection, and it won't become an issue in the tournament because they wouldn't be able to get any wins in the qualifying week.
Problem: That's a lot of work on Walts end to add this to the game.
Solution: I can go get the wolves.
Note
This doesnt really solve the issue with a certain few people doing good in all the tournaments.