Roger that Exenwyr. However...
The question behind whether somebody is a sex symbol/object is simply the intent behind her design. Samus already has a ton of heroic qualities, and for the longest time she hasn't been portrayed in an oversexualized light. So her fans know her "kick ***, take names, and fly away before the base explodes" nature is not related to her gender at all. We know Samus for the heroic qualities she possesses. The fact that Samus is female is an afterthought, irrelevant to her qualities.
And, whether or not Samus' clothing in Zamus mode are appropriate... well, she's basically acting like a covert agent in deep space. She can't be wearing a parka. She goes crawling through vents, doing flips, shooting the carp out of space pirates... she would logically need mobility. So, of course, something skin tight would suit that. Ponytail? Best way to keep long hair from getting owned by your surroundings is to keep it tied up. Her outfit and costume makes sense.
I think, however, that there are a lot of people who aren't acquainted with Samus' character that will get a radically different impression from Zamus. She will be to a bunch of new people as another hot ninja heroine. Don't get me wrong, I'm for the hot womeninjas. But Samus isn't just that, and I think putting Zamus in this game will give people the wrong impression.
Summary: I think that the nature of having Zamus in will make her appear as a sex object to people unfamiliar with the Metroid series. There is nothing wrong with her character design--unless you think accurately portraying female anatomy is inherently bad--it is the fact OF Zamus' presence that makes her seem like a sex object.
