You have to wipe data when moving major android versions or changing large portions of the framework etc. That's why AOKP reccomends data wipe with each flash. Regardless, I came from stock 4.0.2 to AOKP 4.0.4 which is why I had to wipe, you'd have to do the same flashing most any ROM at that point.
Yes, I reset Google Wallet before wiping data when flashing from stock to CM9. It's just a bit of a hassle to have to do it when flashing nightlies which is why I'm running CM9 instead of AOKP.
Google Wallet is accepted almost anywhere around here (Rochester, NY) because almost everybody has paypass terminals now. In fact it's rare that I CAN'T use wallet.
PayPass penetration has probably only reached 5-10% of all POS systems nationwide. Eric Schmidt of Google
suggested last June that 1 in 3 POS terminals would support NFC within a year but those numbers seem far off. Additionally, Wallet is only compatible with Citi credit cards and two or three phones. Wallet is dying, to be honest.
Google's only hope is that the NFC POS that
Isis will use is compatible with Google Wallet. It's rolling out soon and hopefully it will hasten the penetration of NFC POS systems. Also, one wonders what Apple will do but they're usually late to the game.
However now I can't use it all. I'm very surprised no one has figured out a way to fix this yet.
For everyone's sake, I hope that Google can fix this in a future update. Good luck.