1) I've played it quite a bit, finished Single Player mode twice on my own even. It's a good game but would seem redundant when I have newer games, and older games less familiar. I'm just not in the mood for it today.
2) It seems a bit lazy for the game still to be the same. If I'm going to go back to it, Nintendo's got to add some content. It has to be free because my time is valuable as a resource and I'm already making sacrifices to be a gamer.
3) Where is Sonic? I don't even like Sonic anymore, but man those games used to be good. There's no reason this one thing from Nintendo shouldn't be exactly the same as that one thing that was good. If Sonic 2 can have a great soundtrack and be remade on 3DS, there's no reason that Mario Party 10 can't have online play.