Strong Pokemon... Weak Pokemon...
That is only the selfish perception of people...
I'm just noticing a few things that don't really work here.
First off, running one Uber is strictly not permitted for Leaders, Elite Four, or the Champion. The only place where that is allowed is the Frontier.
Secondly, the Guild does not run the Item Clause, so that should just be removed from your rules list.
Once you touch up those things, your Gym should be set in stone and ready to accept challengers.
Truly skilled Trainers should try to win...
With the Pokemon they love best.