I updated the poll today. Here are the results from the last one:
What's the biggest flaw in the demo?
Right click-based mouse system
Able to only play as GDI
File size/Long lines; I haven't downloaded it yet
I'm not interested in the demo
Total Votes: 272
This was pretty evenly spread out. The old-timers seem to want walls and a left-click play system, which isn't surprising. Obviously, the huge file size and long lines were also a problem for some. We'll ask this question again once the game comes out to see if things change.