In his career of about 50 years, Iron Man has had the pleasure to wear plenty of different armor designs. This infographic by HalloweenCostumes shows the progression of Iron Man’s armor through time, showing the most popular suits. What we do see in the early Iron Man suits/armor is the progression of nipples. It would seem Iron Man’s armor nipples started around his tummy and steadily moved upwards; after spending some time at their anatomically correct position, they seemed to have moved further northwards and disappeared.
I think I speak for everyone when I say armor nipples would not be missed, unless they started shooting lasers. Then they would be a matter of immense curiosity. Still way better managed than George Clooney wearing a batsuit with nipples. What were they thinking? Which reminds me, what am I thinking? Now would be a good time to stop talking about dude armor nipples.