OK, if you want them in order, I'd put them as follows:
With the sidenote that I really hope Mischa proves me wrong and gains in consistency. While I do agree with Nathaliia that he can play on clay better than Tsonga, he is still extremely vulnerable, and I see this vulnerability as an inbuilt tendency in his game. But, as I said before, the most interesting style out of all players.
I am hoping Gulbis, Cilic and Tsonga will not do as well as I predict. They rely so much on power
If this is tennis' next generation, it will be a snoozefest for me.
Cilic especially is extremely boring to me. Tsonga at least has the showmanship to fire up a crowd.
Young is really a wild card here. He could either develop and go far, or could completely flunk. So I just ranked him in the middle of the pack because I simply don't know.
Bolelli is a really nice player to watch, and I think he can play on all surfaces including grass. He's got quite a good net game too and I don't agree with people who said he is mostly a claycourter. However, I think he just is not good enough to reach the Top 20, while I can, unfortunately, see the likes of Cilic get there relatively easily.
Querrey for me is just bland. He has completely failed to impress me, but could have some outstanding results with his all-power-and-no-intelligence game.