The Wonderful 101 is probably going to be on the short side, judging by a comment from director Hideki Kamiya. But, responding to the flare-up of controversy caused by that comment, executive director Atsushi Inaba attempted to clarify.
It started with a tweet from Kamiya (via Siliconera). "If u hate to finish a game the next day u buy it, u better not play TW101," he said. "I focus on how it is fun, not how long it lasts till the ending."
That sounds like an admission that the game will be short, but Inaba responded with a long series of tweets. "What he is saying is his basic approach to how he creates an action game. The idea is rooted in that you shouldn't pad your game with content users won't enjoy in order to control play time to the end of the game. It isn't something he wants to do, or thinks you should do."
He says that Kamiya actually tends to put a lot of content into his games, and that in his past experience he's never worried about game length. In fact, he says, as executive producer it tends to be his job to order cuts when a game is too long.
"Of course, even though @pg_kamiya didn't intend for people to jump to their own conclusions, they did," Inaba said. "In this case, that conclusion was 'So TW101 is going to be short then?!' Let me make my own conclusion: TW101 will be so much fun you are going to wear out your Wii U GamePad. Actually, the Wii U GamePad is pretty sturdy, so you probably won't wear it out."
It's notable that he didn't make any direct statements about the game's length, and chose instead to focus on his past experience with Kamiya. He said announcements are forthcoming, and with E3 just around the corner, it's a safe bet that we'll have a new look at the game then.