I looked back at my last return and I think that it might be possible for a lot of US expats to do a ROTH even if they use the FEIE as your ROTH contribution is calculated based on your Modified Adjusted Gross Income which is your Adjusted Gross Income (AGI) PLUS your FEIE and housing exclusions. The IRS taxes you on your AGI which might be quite small, or nothing in my case, if you take the FEIE, but then you get to add that back on for purposes of calculating the amount you can put in a ROTH.
This seems a bit too good to be true, am I missing something?