Heh, for a minute there my first thought was MY times bad saturday morning cartoon art style... Then I remembered that its actually... today. Yeah, totally.
Honestly, its not SUPER horrible, the worst part is that they completely botched the helmet, making one of the most iconic images in videogames rather unrecognizable in shape and definately by silouette. Big no no.
Aside from that, if it WAS a saturday morning cartoon, it wouldnt be too bad. However, its a videogame, a metroid videogame, and as such, that art style, the bold simplified graphic design style is a horrible horrible fit for a metroid game.
Not even so much because of the Samus design, but because of the design of the rest of the world that would have to match. Metroid is a very very detailed game world, Especially from super and onward. both visually and auditorily. This art style is not conducive to the kind of overly attentive subtle visual detail Good metroid games are built on.
As much as I would love another metroid... It looks like Nintendo made a good call on this one.