Just thinking out loud here...
Is there any reason, other than political expediency, that Supreme Court justices should be lawyers? Would it kill us to have, for example, a philosopher? A businessman? A farmer? A poet? A politician (OK, we have some of those, but aren't they lawyers anyway?)?
The more I consider the issue, the more I think it would be wiser to have most Supreme Court justices not be lawyers, but instead be from a broader spectrum of fields advised, if need be, by a staff of clerks who are lawyers.
In limiting potential justices to lawyers, aren't we guaranteeing that the Court will lack the competence to rule on issues involving ethics, economics, politics, medicine, religion, etc? It seems to me that we need either to restrict the number lawyers in the Supreme Court, or restrict the effects of its rulings beyond a very narrowly-defined arena.
In the interest of full-disclosure, I myself am not currently a candidate for SCotUS, but if asked, I will serve.