Looking at Tokyo Disney's ticket purchase section, it seems there's no equivalent to WDW's Park Hopper. Just a 1-Day Passport allowing access to only one of the parks. Am I missing something? That's unfortunate. I routinely visit more than one park in a day at WDW. Probably a max of three in a day. Then again, I know how to navigate those parks and don't mind lots of brisk walking.
In fact, unless it's wall-to-wall people, I'd probably try to visit both Tokyo Disney parks in a single day were it possible--just to get a taste of what it's like. Obviously it would be a superficial visit; and some would balk at the idea. But it would work for me.
http://www.tokyodisneyresort.jp/en/ticket/