When thinking of the court of last resort in this country, the last thing I think about is whether or not the court 'looks' like America.
These are not elected positions, nor do openings come open very often. When they do, the best and brightest should be appointed with a complete disregard for whether or not the 'face' of the court 'matches' the demographics of the country.
That being said, it looks like a lot of business related issues could stand a chance of coming before the Court, and a lawyer with lots of practical business experience would add a good dimension to the Court.
Whether Miers is that person remains to be seen.