I don't know if I'd enter Large Piece competition every week, maybe just from time to time, but yeah, it's a good idea. Although I agree not many people will enter them unless the themes are really friendly...
Another idea, on another graphics forum, the have a rotating competition where I think it is every fortnight or a month or whatever, but it changes from tag, to LP, to icon each time it is held. I think something like this could work (without LP probably) because it means sometimes there will be two themes going, so if someone is turned off by a theme that they have absolutely no intention of entering, they might enter one with a different theme that happens to be on at the same time.
Another idea, on another graphics forum, the have a rotating competition where I think it is every fortnight or a month or whatever, but it changes from tag, to LP, to icon each time it is held. I think something like this could work (without LP probably) because it means sometimes there will be two themes going, so if someone is turned off by a theme that they have absolutely no intention of entering, they might enter one with a different theme that happens to be on at the same time.