AIM tried to recruit Hank a couple times in the comics so having Hank join AIM and try to turn the organization into a force for good would of been interesting if Sunspot had not already done it.
I think they could probably still do a 'Hank Pym joins AIM' storyline but with Hank acting as a mole inside the organisation. Everyone thinking Hanks gone full villain but he is secretly trying to bring the group down from the inside and feeding intel to the Avengers.