Hated Skyline in C2, still hate it now. Probably simply because in C2 every second match was on Skyline...
Anyway, Williamsburg is actually a remake of one of the C2 DLC maps (Harbor I think it was called), but apart from that, unless there have been plans to remake other C2 maps for a while, I think it's not really likely. And I will think that should the paid DLC include remakes of some of these maps, a lot of people might be disinclined to buy "old" maps - unless the price/map ratio drops significantly from C2.
I wouldn't mind paying 10$ for 6 maps, three new, three C2 remakes, but I would not pay the same for 3 maps, 2 of which are remakes of C2 maps with more plants...