If they were to do a full rebuild, theyd do it wtih an XPac. Though from a standpoint, there is not enough driving reason fro them to do one. Yes there are limitations that annoy the player base, but because its popular as is, nothing is prompting htem to fix it. There is not enough outcry that it would be more cost effective to fix the issues than ignore them.

If the player base were to suddenly shrink due to coding issues, or because competition drastically pulls players away from the game due to outdated mechanics/coding, you can bet youll see it become a priority. But as long as profits are stable or rising, its not at the top of the agenda from a business stand point.