It seems that Skuzzy has stated that DX9 is the farthest that HTC would dare to tread for fear of losing XP customers. While this concern is valid, there is another solution. There could be multiple versions of AH2; the only difference being client-side DX10 and DX11 for some, and ported DX9 rendering for others. All other elements would remain the same, and each version would send and receive the same packets to and from the server. The only difference is that those with higher capabilities would be able to use them, with little to no cost to XP users. Therefore, everyone would profit from better rendering or just regular updates, and the arenas would remain intact.
-Penguin