I'm going to this!
As far as a TCG league....I certainly play sometimes, but I wouldn't want to be a leader. Casual (e.g. theme decks) and competitive decks are wildly different. For example - if you have a deck on par with theme decks and face somebody with a competitive standard deck; your first turn, you might play a couple pokemon, attach an energy and equipment, then pass, while the other person searches their deck 3 times, then draws 7, searches twice more, sets up the bench a bit, and then ends the turn by drawing 10 cards with an active pokemon that will attack for 150 every subsequent turn (enough to one-shot your entire deck).
That might be a little exaggerated, but the main thing for me is that is TCG games often take a really long time (so much searching and shuffling), are a lot less fun to be on the losing side of than the video game, and (most importantly) I'm more looking forward to playing things like 2 Rooms and a Boom or Food Chain Magnate or just new games in general. It would be super awesome if you could get it running though, I'd say go for it (It might actually run smoothly with 3 prizes or some other sort of rules modification).