With virtual product launches having become a necessity, if not perhaps on their way to being a norm, Apple can announce a new Pro, or any product, whenever it is ready to.
The necessity to adhere to rigid schedules, as in the past (Apple would have looked foolish with nothing to show off at its huge booth at the MacWorld Expos in January, which forced its employees to work during the holidays), are long gone.
It may certainly wish to maximize the hype and wait for WWDC, but it will already have plenty to offer then, at what is a software conference anyway.
The only remaining predictable launch is the Fall iPhone event. And even that has seen shifts due to development schedules.
Otherwise, trying to predict the future based on the past, while entertaining, is increasingly becoming even more of a guessing game with poor results. Especially for a company that now has the market power and level of attention it lacked in the past.