I agree with everything you are saying :D
The B [Bits] part really is odd.... there is nothing in the box that makes you go "wow" and yet the sum of the parts is beautiful.
In terms of R [Replayability] I think it worth mentioning the characters.
Every game is modified - all be it very slightly - by the traveller you choose. Get the old guy who likes his baths and stopping off in the hot springs now becomes a bit more tempting. Take the Shopahplic and make sure you grab every chance for a souvenir.
The changes the characters bring are actually quite subtle... they don't offer a huge points difference so how much do you modify your behaviour based on their whims? And how often do you deny your opponents their bonuses if it does not directly help you?
It is all calm and nuanced and - as you said - borderline serene.
And not always as light and fluffy as it appears on first look :devil:
One final point - I think this game really hits the sweet spot with 5 when you get to use the full board (baubletastic) and stations start to get cramped. And, yet, it is a pleasure with any number...