There is absolutely zero chance this game won't sell 2m. That's a guarantee.

It will disappoint me if it sells less than 3.5m LT.

It will sell more than 3 million.

To disappoint me? That would be if it sold less than 2.5 million.
Personally I think that SMM is kind in a weird territory because I think that people would treat it like a 2D Mario game and that it will sell like one, but I also think that some people would treat it like a spin-off title and would be prone too wait until the next 2D Mario.

Less than 1.69 million

There is absolutely no reason this should not be a massive hit. Honestly, anything less than 4 million is a failure for Nintendo's marketing team.

If it sells less than this: http://www.vgchartz.com/game/47092/super-mario-all-stars-limited-edition/

It should sell over 2.5M-3M LT. otherwise, I'll be pretty disappointed.

Typical

but I'd be disappointed if it sold less than 1M

I'd be disappointed and mildly impressed if it sold less than zero units.

Less than Splatoon would dissapoint me.