By rotate do you mean have a different course each week for thge weekly tournaments? Because this already happens. If you mean make some of the ones currently only available for CTTH full courses this isn't possible. Those courses weren't fully photographed and mapped. Just enough was done to get the CTTH working.
And I'm afraid throw in is a bit of a simple expression to describe the work and time that goes into getting a course added to WGT. There's a lot more to it than going out and taking a few photos, as far as I know about 100,000 of them. The terrain also has to be mapped which is probably a massive amount of work. Then there's the small matter of paying for the licence.
We all slag WGT off now and then but seriously, it is an incredible achievement to get such a realistic looking golf game running. It has it's flaws but what doesn't?