I think that making it only 1 thread wouldn't change the course of the tournament that much. Probably all voters would keep voting, it's just a matter of letting everyone know in the first post and in the thread title. Let's wait for other responses to the topic, if more people complain we can change it IMO
Regarding the DC issue, I really think we should do it. World Group ties and the WG play-offs in the end of the year wouldn't be much work. No need for Zonals though.