: Yeah, Garrett and I just had a similar conversation about this. One of the
: reasons I chose this as a subject is because I have a hard time seeing the
: evolution from the Mk. I in the comics to the Mk. III[b], for the same
: reasons you described, and wanted to see how others rationalized the
: progression visually. I think Garrett's done a great job here.

Hell, it seemed pretty straightforward to me.

: In my head, I think about it as: the Mk. I was originally intended to be what
: the Mk. IV was, and they realize the only way to make it effective was to
: work more towards the mech direction, to account for the lack of tech they
: had at the time. It wasn't until Halsey came along with her big brain and
: was able to reimagine what Mk. I was originally trying to achieve that
: they started slimming it down again..

I like to think that the progression was driven by the need for power and protection. Mk. I required tethered power and was underarmored, so they bulked it up for Mk II. The second Mark still couldn't mount a large enough power source and the fuel to keep it running in the field, so the Mk. III was made larger to accommodate a wireless energy receiver. And since walking in the Mk. II was like walking in a fat suit with a saddle between your legs, they just made the Mk. III large enough to house the pilot in the torso.
At which point an oversight committee saw the diminishing returns and mission creep coming and nixed the whole project.