Zelda U to feature side quests.

Outside of a few occasional missions most side quests in Zelda games are usually tied to the main quest line. Unless we're talking about Majora's Mask (GK-UK's favourite Zelda) which was filled to the brim with side missions.

But it seems Zelda U (would really like a name, so I can stop calling it that) will inherit that trait from MM. Game developer legend Shingeru Miyamoto "Their may even be times where you forget what your goal is because you're doing other things on the side," Miyamoto explained in an interview with iJustine. "There may be times where you go into one big, long dungeon or there may be times where you're headed to a dungeon, and you're doing other things along the side."

Abe's Take
Whilst certainly a welcome addition to the increasingly impressive looking U exclusive some "fans" are crying foul. Claims that Nintendo are "pulling a Skyrim, by trying to hide a week plot under a mountain of side quests". 

I find these "fans" complaints invaild and rather a testiment to Bethesda's world building skills. That the very world is more interesting than any "event". Zelda games aren't really known for their plot but rather the quality of gameplay, so to suggest Nintendo is some how lessening that by adding more game is... Comical at best.