I'm not sure what Imai will look like at the big league level, but I think with Bieber back in the fold, the Jays can afford to take a chance on upside now. The "grizzled vets who eat up innings over 162" have value, but as we saw with Yesavage in the playoffs, you really need to add impact where you can. If they feel Imai has that potential, then go for it. The added benefit is that it won't cost a pick like Cease, Suarez, Valdez, and King.
Of course, the Jays adding an impact player from Japan is something I'd actually have to see to believe. Maybe the World Series run (which got a lot of viewers in Japan too) created some awareness with the Japanese market.