The game is gonna get average reviews. Something like 72%. It will end selling good but not great. 1,6 millions is a safe bet. But over 3,5 millions is a wrong prediction. 7 millions is far to much!

I'll low ball it and say 2 million.

I bet it'll get to around 2 million eventually

I'd put it on two factors. The first is how well can it sell in other territories (Punch-Out, despite having good sales, made most of it's sales in the USA). The other is how well does the US like it.

The worse thing Nintendo could do is treat this like a core title; it could easily be an expanded audience one.

I'll bet on a million.

Yeah, that seems pretty safe.

Wow, so you're two factors are (1) how it sells everywhere in the world besides the US and (b) how well it sells in the US?

:P I know that's not what you're saying, I'm just being facetious

Are boxing games any popular? I don't think they're an mainstream as football, etc.?

1 million would be a pretty hot cake, 2 million would be super hot cake, and above that would be mega chocolate cake.

anyone know the sales of the first one?

http://vgchartz.com/games/game.php?id=6401&region=All

Not trying to sound condescending but the Games tab in the menu up top will give you sales for quite a lot of classic games.