>>6013377Only two of them are really considered busy.
One was the original that was made out of craps in a cave and the other one was made to be as flexible as possible.
The rest are less busy than most any knight's armor. They armor protects the person and its inner workings. Just like the armors in the comics.
Again, the Hulkbuster just has all the bits and bobs hanging out, just to look busy and complex. Again, the comics continues with the design of the IMs, except it looks stronger and durable with the added bulk of the extra armor and size.