I wanted to come back and reiterate that AcuraLink traffic via cellular seems to work just fine, and stays up to date at least as well as XM Traffic did, if not faster than XM Traffic.
You'll appreciate the ability to see secondary and primary road traffic information instead of just Interstate traffic, too.
If anybody's looking, although I know that it wasn't of much use, I do sort of miss the radar map of the weather. Since AcuraLink is obviously connecting to somebody's cellular data towers, perhaps at some point we could consider implementing Google, Apple or Yahoo Weather on the big screen of the car.