If its arranged like Ranked Battle. Who is the Top guy going to fight, and if he can't fight, how is he going to get points?
And if the system of Ranked Battle is adopted in Arena... Isn't it just Space Time Battle that can be manually controlled?
And if you want to choose who you can fight, wouldn't both parties in that list have to be online, or else its just fighting an AI, which means its pretty much Survival Trial.