In general, with the Battle Frontier these days it works in that it begins off nice and easy, and then a few rounds in it builds up in difficulty - certainly the 1st-stage evos are basically gone by the third round. Sure, beating a set of seven is easy - but try hitting say 50 (or just beating the Brain twice for the gold print) and it's a completely different matter. (And the battle factory which has rentals is balenced from the get-go in terms of Pokemon - either you both have weak pokes or strong ones).
But yes, Crystal's BF was hax. x_x