If A17 is willing to let you fill in for one of the many defaulted losers.
Undeniable fact: Articuno, Zapdos, Moltres, Raikou, Entei, Suicune, Regirock, Regice, and Registeel are legendaries and therefore aren't used. Dragonite, Tyranitar, Metagross, and Salamence are not legendaries, they're just strong Pokemon. If your team can't beat any of these four, then obviously you've made some mistakes in choosing your team. That's my unshakable belief. Of course, I mean, come on, Tyranitar has 4x weakness to Fighting, Dragonite and Salamence have 4x weakness to Ice, and you STILL can't beat them?