I think it's really neat to see this new generation come up, comprised of Tomic, Dimitrov, Raonic, Harrison, and Berankis. This generation is intriguing because even more so than the generation before them, age and fitness level are crucial. We will see them continue to blossom over years before they are truly ready to compete with the men on tour.
Of the youngsters, I think Tomic has showed the most potential for Top 5 and a Slam win. He's the only one I truly believe will be Top 5; whereas the others, I need to see a bit more or wait before being as confident that they will. I was extremely impressed by the way Tomic played and challenged the best player of the year at Wimbledon. He showed talent, smarts, and shot selection. I do think Dimitrov has a ton of talent to succeed, but I think his key will how hard he works. He will need to be much stronger and thicker to do it, and it will take dedication to transform his body (see: scrawny but talented athlete Djokovic in 2005 when he beat Ancic and made the 4R at the USO).