Moving to early August does have disadvantages; e.g., more cities are likely to have hot/humid weather (a factor when it's ~.4 miles between hotel and convention center, as you describe Denver), and there's also the problem of crowding Pennsic (which is similar in size to D*Con if not larger, still has many con-going attendees, and is spreading farther and farther before its major dates). Losing pros to D*Con is an issue....

/CHip