Someone once told me that a stipulation for public service should involve converting all your holdings into index funds only. Thought that was an interesting proposal.
For most elected officials (that have broad scope of potential jurisdiction and thus are almost impossible to avoid conflicts of interests), blind trusts are probably even better.
For most public servants, even those that have decision-making authority that could potentially raise conflict interests, disclosure and recusal rules are probably all that is needed (and, actually, lots of public servants have no decision–making authority that is likely to even require that.)
Appellate and Supreme Court judges could arguably fit in either category; trial court judges seem squarely in the second.