Suggestion: Add support for Foreign Earned Income Exclusion. If the trend is remote work, focus on the remote workers who would prefer not to pay income taxes.
In theory I'd love a tool that could save me wasting my life on this every year. However, would I trust it? Not from a malicious standpoint but it seems there's been lots of changes over the last few years and I'd need to know the tool had been properly updated. To do that I'd have to go and read all the updates/instructions each year (just like I do now) and then also check the tool was correct. I'm not convinced a (free?) non-accountant DIY method helps when the monetary cost of it being outdated/bugged could be significant.
I guess you could argue that this is no different from any other open-source software and it's my choice to either personally audit it or assume someone else already has - including all the schedules I use. I'm struggling to understand why I have more of a concern with this compared to, for example, my web browser. Perhaps I am just especially (and irrationally??) fearful of the IRS and the consequence of getting taxes wrong.
Expat workers seem so niche and there may be different requirements depending in their specific situation.
Part of the problem is a pervasive sense that if your are an expat, you are somehow guilty of something or not patriotic enough or some other undefined sin. All of US law seems to expect that you are US resident, yet we apply it globally.
My taxes are much more complicated because of this and I think a separate niche tool would be better.