Nintendo confirmed via press release that they will be putting it back on the eshop at 29,99$ instead of 59,99. I don't know why they had to remove it to change the price though.

so people will talk about it in places like vgchartz

nintendo making indirectly advertising once again...

Maybe too many copies were produced and they're trying to do everything they can to sell inventory. As good as Nintendoland is (a must play, in my opinion), it wasn't the mega-hit they were hoping for. Now that it's not bundled, it could be a good game to buy as a gift or something.

Clever, a move to empty out some warehouse space taken up in the US by copies of this game, would explain why it wasn't taken down from the EU shop since different region would have different boxart and copies of the game.