One way to reduce the complexity of our tax system and the rent-seeking/tax-favor-hunting behavior it encourages would be to simply cap the amount any one tax payer could get in tax expenditures an individual could take. From the politician's point of view this might be particularly attractive. It would allow them to grant special favors to the more worthy (or politically influential) of their constituents without costing the public treasury.
Of course, how long would it be before certain tax expenditures were exempted from the overal cap? Would there be some way to means test this cap? It might make sense to exempt the cap for expenditures that are targeted at very low income people, say people who have high medical bills or something. Though that may be already taken care of in their proposal in the provision that the cap apply to the Adjusted Gross Income (AGI--wasn't that the insurance company that went bankrupt?).