well with ranking systems its always gonna be tricky i mean every one seems to wanna rank up quickly personally it really doesnt matter to me i just wanna battle lol but if you do care about ranks and alot of ppl do, you should test them on there knowledge of the pokes and not just battle skills i mean any1 can get lucky in a battle.
Ask them question and give them a time limit to answer so you know that they just didnt google the answer the questions should deal with breeding certain pokes, how to pass iv through breeding, whats the best way to get a hidden power, and give wat to do in a certain battle situation (ex. when faced against a gyarados that has dd, waterfall, earthquake, and taunt and you have a infernape out on the field with the moves close combat, grass knot, fire blast, and a filler move what do you do?) you know stuff like that questions that are easy but not to easy.
and im not saying dont test battle them only use question's i mean someone could get all the question's right and be a terrible battler or vice versa try to put questions and battling together as a whole test to see who has the know how to be a higher rank oh yeah the question and battles should be harder as you go up in rank.
oh thats a great idea use diff tiers in certain rank battle's that should be good make them familiar with all tiers not just ou, yeah that way there will be more uu battles yes (thats just me talking lol)