The only reason I would love to use the mouse wheel is because I want to be able to have a quick snapshot of the previous and next month fast – especially when there are months like February where the 1st of the month is the 1st square you see, there is nothing left from January.
Without going into the scroll wheel however, do you think it would be desirable to always show at least one day of the previous month on the calendar? See, if the 1st of the month is any other day than Sunday, it’ll always show the last 1-6 days of the previous month, where as if it’s on the Sunday is doesn’t – so whereas you can see weeks into the future, you can’t even see one day in the past.
I guess you could call that (option?) “Calendar Centering”…