This is a nice idea in theory but the reality is it is next to impossible and has too many complications. Your issue is really with enhancers, not with plat itself, because you can fairly easily drop gear that is (IMHO) slightly better than the Plat gear for PvE. Who doesn't use the free daily enhancers? Would you consider for the non-plat leader board people who don't use Plat weapons and armor, or who don't use enhancers, or both? Would the free enhancers then not count?

More importantly, would people who don't use plat then be looked down on by those that choose to support the company that makes the game? If it weren't for Plat users, non Plat users would not have the game to play. This is not meant to offend, just to keep things in perspective. This has been pointed out by others in many threads before this anyway.

Providing the names of non Plat users to cap could be a nice compromise! I like that idea better.