I thought it would at least reach 20k

I hope Nintendo suits really understand why MoM sales are way below expectations 

A lot of fans hate the direction Samus and Metriod are going. I hope they don't live in a bubble like Washington politicians.

If Reggie's comments are anything to go by, they got the message.  They did the same with Zelda previously (TWW to TP), so I bet Sakamoto's next Metroid will be very much a more traditional throwback design and narrative wise.

Here's to hoping 

I believe if it was more traditional it would have been close to million at this point

But The Wind Waker was loved critically and most fans loved it.

It's basically Fusion in 3D with expensive-yet-crappy CG cutscenes... so hopefully the next Sakamoto Metroid will basically be Super/Zero Mission in 3D (but without the crappy-yet-expensive CG cutscenes).  The base engine is great though, and the mechanics are solid... I'm personally hoping for a 3DS Metroid II remake using it.

TWW was pretty split critically, though it did get high-ish scores.  It's pretty divisive among the fanbase too, unlike OOT or even TP comparably, and it was a definite sales disappointment.  

A lot of that was attributed to it's aesthetic (which I loved personally) and it's ocean faring overworld design (which I hated), so it's no surprise both things were dropped for the next Zelda.  I think we'll see the same for the next Metroid (ie: less intrusive voice/CG/cutscenes, more open world design/progression on an actual planet, etc).

http://www.metacritic.com/game/gamecube/the-legend-of-zelda-the-wind-waker

Your first two statements are patently untrue. Wind Waker received universal praise among critics, and its metacritic score is among the highest of its generation (or series). Similarly, Wind Waker's vocal detractors in the fanbase are mostly silent and gone, with TP taking its place as the divisive game.

Granted it was a sales disappointment.

Your fanbase argument seems heavily subjective... personally I remember a LOT more controversy around TWW than with TP.  With time things tend to die down, but at launch TP was universally loved, while TWW was pretty split with fierce proponents on both sides.  TP is pretty easily the less controversial game (being more traditional tends to inherently do that), even among the diehard fanbase, and with time it'll probably be universally loved in retrospect (it's already getting there).  Even still, it's backlash is tame compared to TWW (or MM) in it's day, the worst thing about TP critically was exactly why it sold so well; too samey.

Also, TWW being critically split isn't patently untrue, though it still got high scores (which I uh... already said).  Again, same applied to Majora's Mask a few years earlier... I don't think the two statements are mutually exclusive.

Well of course it's subjective, anything based on casual observation is necessarily subjective. Pointing out that subjectivity seems redundant, though it's made weirder when you follow it up with a "personally".

Wind Waker being critically split is patently untrue. It has three reviews that scored it below 90 - of those, two were 89. The only game in the franchise to review better than Wind Waker was the original release of Ocarina of Time - it actually outperformed both versions of Twilight Princess with more reviews than either. This is about a lot more than just the score, it's that the lowest score for it is an 85 and it's the only one more than a point away from 90. If Wind Waker's reviews were split then there is no game without split reviews, which robs the distinction of any meaning. Wind Waker's reviews were not split, they were universally high.

When a personal observation or reflection is labeled "patently false", I'd say it warrants bringing up it's inherently subjective nature.  Sorry if you find that redundant, by your language it wasn't clear you'd find that the case.  Maybe I should've been clearer originally too.

Also, you seem to have some issue separating raw score from a deeper critical analysis.  Lots of reviews found fault with TWW, from it's stilted overworld trawl, to it's late game forced fetch quest, to it's lack of dungeons,to it's utter lack of challenge, but all the same it still scored highly. And even though in much of the press it's aesthetic went from "kiddie" to "charming" when they finally reviewed it, it was still a strongly divisive element. TP's faults were talked about upfront too, but the worst it really had was being too samey and derivative, and still being rooted in the basic N64 design.  Still, I'd say the critical reception wasn't as varied as TWW (or MM), it was more uniformly liked, even if it scored similarly.

A game which truly had near no split reviews would be OOT.  It's probably the only 3D Zelda to really hold that distinction without question.