It's much more complicated than just having a foreign income exclusion and being out of the country.
If your income is above $100k, you also have to fill out the AMT worksheet, which may result in you needing to calculate everything to deduct the foreign taxes you've paid.
If you have US stocks and sell them, you have to worry about paying capital gains taxes to the US (they consider this US income, regardless of if you received the stocks as part of your employment), and you generally have to pay taxes to the country you're living in for that as well. If you're lucky you might be able to deduct the US taxes or expected taxes, otherwise you might not be able to do so or might not be able to do so until the next year.
You also have to report your overseas accounts every year.
When I first moved overseas, yes, it was pretty simple to just fill out my 1040 and my form 2555. Last year I needed those plus the 1040 Schedule B and form 1116. Next year things will get even more complicated since this year I bought an apartment, so there's a mixture of rent deduction and mortgage deductions, plus a significant capital gains tax burden due to selling stocks for my down-payment on the apartment.
If your income is above $100k, you also have to fill out the AMT worksheet, which may result in you needing to calculate everything to deduct the foreign taxes you've paid.
If you have US stocks and sell them, you have to worry about paying capital gains taxes to the US (they consider this US income, regardless of if you received the stocks as part of your employment), and you generally have to pay taxes to the country you're living in for that as well. If you're lucky you might be able to deduct the US taxes or expected taxes, otherwise you might not be able to do so or might not be able to do so until the next year.
You also have to report your overseas accounts every year.
When I first moved overseas, yes, it was pretty simple to just fill out my 1040 and my form 2555. Last year I needed those plus the 1040 Schedule B and form 1116. Next year things will get even more complicated since this year I bought an apartment, so there's a mixture of rent deduction and mortgage deductions, plus a significant capital gains tax burden due to selling stocks for my down-payment on the apartment.