If the US really must do Citizenship Based Taxation, I have a recommendation.
Adopt the Eritrean model.  It would be far more efficient and effective.
One simple form. Two percent of income. Send the check.
This will save the IRS far more money than they currently raise through CBT and will significantly reduce costs.  One downside is it will put lots of IRS Agents, lawyers and accountants out of work.
My consultant fee for this advice to US Treasury:  A significant donation to our Canadian Legal Challenge of FATCA Fund.
Oh wait.  If they simplify CBT, they don’t need FATCA and we will not need to challenge the Canadian government. Unless, of course, FATCA is about something other than taxes.
Many thanks to Em for the great find of the Eritrean tax form.