There is some incentive to vote strategically, but depending on the range and the other candidate on offer you might be better off voting honestly. If there's a candidate you dislike strongly, and a major candidate you only mildly dislike, you might give your favorite a 10, the mild dislike a 3, and the major dislike a 0, just to reduce the major dislike's chances. The worst case scenario, which you describe, is called bullet voting, and is basically identical to our current system, but if even a small proportion vote honestly it can improve the results. The researcher who made the graph at the bottom of rangevoting.org ran computer simulations of voter preferences compared with candidate values, and found that something like 10% of voters given their honest preference can improve results. I do recommend the book if you want to know more.

I am very interested in delegable proxy, although it seems potentially dangerous and I think if it were implemented it would need to be tempered with some less democratic devices, but it could certainly make for some interesting drama.