I can definitely see better micro giving the AI an advantage, but it seems like it'd have to have at least competent strategic play to still do well; it's hard to recover from
completely screwed-up build order. It'll be interesting to see how it plays out, though; if bots in the Starcraft AI competition (
http://eis.ucsc.edu/StarCraftAICompetition) do start winning exclusively through insane micro and a hardcoded rush in the first 2 minutes, it might need to be changed to stay interesting.
To me, the most interesting part is seeing what kinds of AI architectures can simultaneously deal with real-time action across all the levels of complexity--- micromanaging individual units while also making unit-group-movement decisions, build-order decisions, expansion decisions, teching-up decisions, etc., which coordinate with each other. That might need a different game or a variant, though; it's possible that Starcraft is now too much like chess, where people have already mapped out giant databases of opening books (you can find detailed information on various SC wikis about exactly when to build different things in which order, what to build to counter other strategies, etc.). So it might be that a computer perfectly executing one of those hardcoded strategies with perfect micro is too close to optimal to be interesting. But I'm not sure that's true yet; current bots are actually not too great.
Alternately, someone could make an APM-limited variant to handicap the computer a little closer to human clicking speed. That would introduce a strange optimization problem where the AI would need to optimize its click usage as a limited resource.