You make an excellent point MichaelB, but there seems to be a war on anything foreign. That's not unique to the US, the UK for example has tightened up residency rules for tax purposes significantly. What does make the US much more unique is its citizenship based taxation, the only country in the world to have this system of taxation.These regs are a burden, that's for sure. They are affecting too many individuals that don't contribute meaningfully to the tax system.
There must be someone in Treasury or the IRS looking for a way to reduce the workload. For themselves, I mean, as neither has the workforce needed to ensure compliance, and the complexity here makes that a highly skilled labor intensive operation.
The US Tax Payer Advocate has campaigned for a change specifically to current rules for expats for the last 3 years. Both political parties' overseas organizations are campaigning against current rules, and expats have literally (and I do mean literally) bombarded both the Congress and Senate with pleas for review of the system.
The problem is obvious. No Senator or Congressperson wants to propose a Bill that would do away with CBT. It would be political suicide. We also have had several Treasury/IRS Directors who are adamant on penalising anything foreign, with the knowledge that it is harming US expats abroad. It appears they're afraid of relaxing the rules even slightly will encourage the "rich" to take advantage.
CBT, for the near term, is here to stay and Congress keeps attacking the "rich" with no regard for expats. Look at the just passed, and signed by the Pres., Transportation Bill. It contains several tax aspects, with the revocation/cancellation of passports for those with a tax liability. Not necessarily difficult for someone living in the US, but of extreme difficulty for an expat living abroad. (The threshold is $50,000, but the penalties relating to anything foreign can have someone there quite easily.)