Thinking along the same lines about an IM3 connection, and just brainstorming here:
What if Arnim Zola becomes MODOK?
The characters are very similar in concept and look; it's just that Zola has "normal" humanoid limbs, while MODOK has mutant-baby arms and legs, and floats around in a chair.
But other than that, it would be fairly easy to evolve Zola's character into that of MODOK himself, and that would create a direct tie with AIM (which features prominently in IM3) as well as introduce one of Cap (and Marvel's) most iconic foes. Plus, MODOK/AIM makes more sense as a puppet-master for WS than Zola alone does.
Whaddya think, anybody? I'll run it up the flagpole and see who salutes, or throws rocks at it.