VNC to some old Risc PC? Yup, that's gonna sell RISC OS.
The fact is that we're not going to attract Windows users because RISC OS isn't as good at doing the kind of things that your average, home, Windows user does. I.E. web browsing, emailing, IM and office apps. Oh, and forget trying to plug in any random scanner/printer/gps/etc that you'd like to buy from PC World.
If we're going to win anyone over we have to work out what RISC OS is better at. Drag and drop is fine but from what to what? Dragging a Paint file to Draw is alright but dragging a jpeg into Ovation (or something that is actually actively developed) would be more impressive. What else have we got? And more importantly, how can you use these advantages in the types of jobs that people actually do?