1) there exist no balanced asymm maps (therefore i can't provide an example of one)
2) the relatively few asymm maps that do exist are not balanced
3) any difference can always be exploited
4) different differences are fundamentally better than one another (tech > economy) ... which, btw, was not how i interpreted that article you linked. what i took out of it "hit then where they're weakest" is that if they go econ, then their tech is weakest so you tech in response: it's your best response, but it doesn't mean it's strictly better. in fact all three races are essentially like rock paper scissors in terms of their strengths/weaknesses
5) things are complex enough as it is without the map being an additional variable; perhaps even different races can never be balanced