Its just a guess, and it can be a terrible guess, but I feel Chung and Rublev as the most promising young guns of today, but unfortunately not for the slams of this year yet.
Kyrgios is already a big reality to reach deeper stages of a slam (I dont like him that much, but we need so much someone to threat the favorites)
I can be wrong, but I still cannot see Coric and Zverev as players who can go deep constantly on a slam, but of course they can develop their games, they still have a lot of time. But I think they have more gaps today in their games than the others.
I am very skeptical about Kokkinakis reaching top 15 one day, but he will be there to at least trouble.
We should not forget Khachanov, Donaldson and Majchrzak.
And still, we have a lot of players to watch along the next 2/3 years like Jasika, Safiullin, Fritz, Luz, Kozlov, Tiafoe, Halys, Lee, Coutet, and even Auger Aliassime, but that its not clear yet what kind of positions theyre gonna occupy yet.
Sad that Monteiro, Quinzi and Garin are out of the top 200 today.
But yeah, its likely we have to wait until 2017/18 to all finally start changing for real.
We're living a enourmous generation gap, bad for the game, that made a false impression of Fedalovic as unreacheable gods, and that created boring fanbases.