I like where you are going with all this, but I'll nitpick here that while tying politicians' wealth to the overall stock market in general reduces their incentive to legislate in favor of particular companies, it does provide them incentive to legislate in favor of corporate America in general. We don't need laws that help stock market participants. ~50% of Americans don't hold stock in any form, even through mutual funds or retirement accounts.
I don't know what the solution is. As long as rule making can disproportionately affect the rule maker's own personal wealth and wellbeing, you have a conflict of interest.