So even you say, if he has to change his suit he leaves himself Vulnerable? So whats the say that Samus dosen't take that moment of Vulnerability and run train on him. I understand that you say his armor has regenerative powers. But even the most well oiled machines break down. The suit that I'm guessing you are talking about is the one that Justin posted a picture of Stark allmost dead in... Right?
First off, it's nice to see a measured response after the sudden appearance of irritating spam throughout the tournament. The moment of vulnerability is very much a what if, something similar to "What if Samus' power suit gets damaged beyond repair?" - "She resorts to her zero suit". Like you probably don't envisage her to have to resort to this, I don't think Tony would either but, as I'm sure you would yourself, I have to point out that he has that option.
Just on the topic of the zero suit and well oiled machines breaking down (and thus far the only time this has happened to Tony is when an alternative universe Scarlet Witch used her hex powers to cut the power for a couple of seconds)... from Metroid's wiki
"When my Power Suit is deactivated, my Zero Suit is the outfit of choice. In the rare moments when my equipment malfunctions, this is all I have to rely on - fortunately, the streamlined design enables acrobatic movement and the Paralyzer is all that I need to get me out of tight spot."
Samus Aran
As to the suit in Justin's picture, I believe this might be the Extremis armour but the only person who could really answer that question is the artist because; firstly, many of the suits look similar, and; secondly,this is actually a fraud picture. Here is the actual armour that he was wearing when defeated by Osborn. I'm sure you'll agree, it wouldn't make as punchy a cover image.
As to the Iron Man I'm referencing, it's the Bleeding Edge suit:
Samus in screw attack is invunerable, so whatever shield he has and whatever damage that would do to her. If if it causes damage would be delt with, would his shield still be up during that moment of Vulnerability? I don't think so Fit, Stark may be smart. But in changing he has to let somthing down, I don't think he can keep his shield up without a suit on. And he wouldn't have a suit on if he had to change it right?
This seems to vary depending on which Samus is being used, and the variations in computer character versions is MASSIVE. However, in all versions, it appears to be an attack that can be easily avoided as she can only deviate slightly from her original direction. The Bleeding Edge suit has 360 vision, for a character like Iron Man this should be easily avoided. Like I've previously stated, the only time he has lost access to the regenerative prowess of the suit was due to a hex, an ability Samus doesn't have.
My argument all along is that Stark's intelligence will see him through and, from the info out there, this is a massive advantage:
"Samus' Power Suit requires immense levels of concentration and mental determination to operate efficiently. At times of great physical or emotional stress, Samus is unable to maintain her Power Suit."
"The neurokinetic user-controlled morphologic nanoparticle bundles that form the suit reside in Stark's body, and form a fibrous wetweb of iron and platinum, that be commanded to form any type of structure upon Stark's skin, such as large boxing gloves, or weapons, including large guns extending from his arms or a light saber-like energy sword with which Iron Man was actually able to harm one of the Worthy during the 2011 "Fear Itself" storyline. The nano-machines can even mimic the appearance of clothes, and then dissociate to transform into the Iron Man armor whenever Stark wishes."
Or to put it simply, Samus is constantly battling to control the power suit whilst Tony Stark and Iron Man are literally the same being.
(At this rate, I'll know more about Miss Aran than the Marvel Universe - I wonder if I emailed Marvel would they give her a comic?
How could you go wrong with a character originally based on Kim Basinger?)