(As far as I know, Iwamoto-X didn't remove the helmet either; Zero got to, though)
He has, at least 3 times that I can remember, but he never actually showed X's head without his helmet. The closest we got was this
Im just gonna guess that since X was built primarily as a battle robot, Light just never really bothered to give him a civilian form, and instead concentrated on making him tougher, stronger, and more advanced in AI.
I'd much rather Reploids be treated like what they are: highly sophisticated, self-aware, silicon-based computers with robotic appendages, senses, and feelings governed by human-engineered computer programming, not biological or natural programming. If they must have DNA, then might they not also have an epidermis with hair and blood vessels surrounding a titanium endoskeleton?
I think you are just overthinking DNA as far as the X series goes. Robot DNA is their source code basically. Contains everything that makes them who they are. Their personality program, their weapons data, even their appearance data. by using that, X and Zero can get new moves based on that Reploid's specific weapon ability. While Axl and New Gens, can use the appearance data to morph into that Reploid, with what i can only assume is some kind of molecular level nanotechnology or liquid metal technology akin to Double's.
You dont have to envision it as some kind of organic thing, after all, when robots blow up in the X series, they still have all kinds of metal junk in them, not guts. and yet still have DNA. If an energy based free floating computer virus can exist, Robot dna can too.
what makes a Reploid a Maverick? Is it the fundamental capacity for free will they've been programmed with, or free-floating viral code they can't defend against and makes them go all mad-cow and stuff? The answer could be either one, which turns this into a socio-political propaganda scare incident not unlike the McCarthy Red Scare.
The very definition of Maverick, is, in the original japanese word- to be "irregular". Which is self explanatory. it means you are not functioning regularly. As far as X series goes, Mavericks are only those who malfunction due to some kind of bug, glitch or virus.
I can only recall once where it was used as a label, and that was X4. But X4 in it's entirety, was caused by one big misunderstanding between both sides perpetrated by Sigma and a traitor within the Hunters. The Hunter hierarchy had genuine reason to declare Repliforce Maverick. They were framed for dropping an entire floating city/highway thing- down on top of the City below, annihilating it. And when it's Colonel was asked to come in for questioning, he vainly refused, and even encouraged the Hunters to call him and his men Mavericks if they wanted. From there, the entire Repliforce declared independence from Humanity. They declared it was not about rebellion, but it just came across as turning tail and running away.
Only once the Energy Crisis started in Neo Arcadia under Copy-X's watch, did the term begin to be misused as a way to commit mass Reploid genocide for the sake of pleasing the Humans. And anyone who would dare oppose this, was also labeled Maverick. When Weil took over, he would declare anyone who opposed or decried him as Maverick, even if they were Human. Afterward, by ZX, the term returns to more or less the same meaning as the X series.
And by Legends, it's meaning seems to be a bit ambiguous, since those who go against the system are considered Irregulars, (Abberants in the English version)but we dont quite know the circumstances there, since it seems the system liked to keep a pretty tight leash around it's Robots, limiting their intelligence, not allowing them to think outside the system's parameters, so it's possible that simply anyone who dared to question the system was put down, along with any who malfunctioned. Trigger rebelled against the System on the Master's last command, and was considered an Irregular.