I have Iron Man comic-books since before I learn to read.
In the first design, the helmet looks too rounded and big, but I like the armor design. In the 3rd pic, the armor looks great.
I don't think that the armor must look more bulky, to carry more weapons... Iron Man is NOT War Machine!
The Iron Man armor don't carry cannons or something like that. The weaponry of Iron Man are:
*Repulsors: Laser-guided particle beam emission units mounted in the palm of each hand.
*Unibeam: Multi-band light and force beam emitter. Can be adjusted for a variety of effects such as search light, heat beams, tractor beam, lasers, image inducers, ultraviolet light, and electromagnetic pulse.
*Pulse Bolt Generators: Plasma discharges that build in intensity as they travel through the atmosphere, picking up static and ambient energy.
*Force Shield: A focused photon emitter on the back of his left wrist that shapes into a shield. (This weapon was never used in this armor but is presumed to be standard issue for Iron Man armor since the Armor Wars)
*Electromagnetic Pulse. (This weapon was never used in this armor but is presumed to be standard issue for Iron Man armor since the Armor Wars.)
( Source: www.advancediron.com )