I love the battle frontier, especially the battle tower. I made a team of Lv. 50 pokemon just for the ruby battle tower that I most likely will never level up again. I used to play at the battle tower for hours, just battling pokemon. Recently, I almost got a strategy together with a poliwag on my SoulSilver game. It went hypnosis, belly drum, and then wakeup slap or waterfall, depending on the pokemon's type. It would be awesome if the battle frontier was implemented in Pokemon Universe.
