I would love to see Armstrong. Also yeah, theoretically Ben can transform into a Stand user, but only if the Omnitrix had its safeguard against mutant forms removed. As it stands (heh), Stand users are (mostly) Humans with a genetic/spiritual abnormality to them, and would therefore be normally unobtainable.
I can see the argument on Stands being overbearing, so here's my be-all-end-all statement on them to simplify things. In the Paradox Engine, Stands are fully visible to all individuals, so that some people won't have to fight against an invisible, untraceable force, but beyond that, function identically to normal. Still means Stands have quite a few advantages on non-Stand users, but it won't make them pretty much impossible to handle unless the character somehow knows prior what will happen with said Enemy Stand User.
....And yes, that's a Jojo's reference.