Thanks. I've gotten pretty good at filling out American tax forms and am happy to continue doing so if that's the only real hassle that my American citizenship would bring living abroad.
Just to say: have you actually filled tax forms out as a US expat? They are not entirely the same as the ones you fill out in the US - and, more to the point, a lot of areas of US tax law as applied to other countries are really ambiguous - and yet the penalties for being wrong are extremely, terrifyingly, high. I have kept my US citizenship, and I do my own US taxes, but it is a much scarier process than when I lived in the US.
I would also, separately, suggest that relying on the earned income credit may be specifically disadvantageous for the FIRE community, who will usually be hoping to shift to "unearned" income at an earlier point than most retirees. I am not an accountant, and accounts who know this area from the standpoint of expats to any particular country are few and far between, but it's at least worth looking at whether it's better to use foreign income tax credits, which can be applied either to wage income or interest/dividend income - particularly if you're living some place with high rates of taxation relative to the US. Also be aware that the treatment of other countries' retirement accounts and pension systems can be particularly complex and, while you'll sometimes read people giving very confident-sounding advice on what to do to minimise your US tax exposure, the reality is that a lot of this stuff just hasn't been formally tested, so it's all a bit tenuous and uncertain.
I'm still hanging onto my US citizenship - but it's not foolish for people to think about surrendering it.
On the 'can you open bank accounts' question: I know people who have had problems in some European countries, and have surrendered their US citizenship as a result. I /think/ this is getting better, as overseas banks adjust and also as various governments get better at lobbying for their immigrant citizens, but all I have here is anecdote...