I should be publishing updates for both Blue Skies and Snowfall later today. Both of these are directly tied into the time of day/location stuff. Basically, we're making the positioning requirement optional in case there are some devices out there without coarse location support.
In Blue Skies the SMS requirement is also being made optional, as for a WiFi tablet (for example) there may not be SMS services at all, and if the requirement is non-optional the Market won't even display the listing. The SMS service for Blue Skies is used to (optionally) display balloons drifting through the scene based on the number of unread messages. As it's a cute extra feature rather than something central to the product there's no reason not to work without it if need be.