There is no plan yet to support Visual Studio 2010 for Rocket, but your feedback is appreciated and we’ll think about it some more. I’d be interested in knowing why you’d want to use Visual Studio 2010 Pro versus installing the Express version of Visual Studio 2012? That is, which features are missing in the Express version that you need day to day?
One of the reasons we decided not to support Visual Studio 2010 was that the Express edition of 2010 doesn’t have a 64-bit C++ compiler included with it, which is required for Rocket programming. The other reason is that we’re generally moving development of UE4 away from the older version of the compiler so that we can use more modern C++ features to make life a bit easier for everyone!
–Mike