The only thing that worries me about limiting submissions is how do you choose who gets to submit? Most likely you pick the people you think will win, and then some poor person never gets a chance to participate because they might not be as "good" as others. :( Same kind of thing with the cap and having to reject members in favour of others.

I think at least one time there was a WAR where potential leaders could make up a team and submit it for consideration. Then everyone would vote for which teams they would actually like to have in the WAR. The top x teams were picked to compete and then everyone could pick one of those teams to join. At least that way it's more likely that there will be enough members wanting to join each of the selected teams?