see if I want to pursue a transfer to my company's Tokyo office
Think long and heard about about this one.
If your company is going to take care of you on a inflated expat package, then sure.
If you're not getting an expat deal (housing, big expenses covered) and have to live as a local... it's not worth it.
At least at this juncture, Japan is falling down in competition among western salaries and perks.
It wouldn't be so bad if the local CoL wasn't increasing so much... utilities, food, daily life items -- all have risen but zero increase in salaries for the majority of workers in Japan.
And so long as the Yen remains in its pitiful state, taking trips out of Japan or just to go home for a visit, will be much more costly if your primary currency is Yen.
OTOH, if you come to Japan and get paid in USD or similar, strong currency, then you're good until the yen value goes up again (if it ever does).
And no, getting a a Japanese passport isn't that great of an option since there is no dual citizen option. But yeah, if you're not from a 1st world country and have no ties to your previous country, then it's a good move.
I started seeing ads for renouncing US citizenship, I wonder what triggered that?
That's something I'd never do.