I don't forget and I've said it many times. I started that post with, "I know he's young." I'm well-aware that Rafa was the last great teenager and Pete and Marat before him. I'm really only reacting to those that are putting a lot on his shoulders. (I think GSM has nominated him for President.) As I say, I think he's got great potential, but he's got a lot of seasoning to get. Likewise, I think Tsitsipas is coming on fast, but even as much as I'm "bandwagoning" him, I don't expect much immediately. I'd say all of these promising young guys at the top of the radar are on track. But I don't see anything wrong with pointing out that they are young and lacking in certain polish. That's all I'm saying about Shapo. Like most, I'm pegging him for real stardom, but he's not there yet. His powerful racquet still proceeds his head.
As far as great teenagers: note the names. Whether or not tennis is aging, I don't expect a Rafa or Pete or Marat to come along every generation, anyway. Who knows when we'll see a teenager like that again, or if ever.
Yeah, I know - sorry, didn't mean to come off preachy. I was more meaning to elaborate what you were already saying.
I haven't watched Tsitsipas play yet so don't have a sense of him, but based upon age-rankings combo (which isn't definitive, but gives us a starting point) I'd pencil him in the future second tier group with Rublev and Tiafoe, behind Zverev and Shapo but ahead of the Coric/Pouille types. Something like:
First tier (multi-Slam winners, regular #1s): Shapo, Zverev
Second tier (Slam darkhorses, Masters winners, regular top 10): Chung, Rublev, Tiafoe, Tsitsipas, Kyrgios (if he ever gets his shit together)
Third tier (Masters darkhorses, multiple 250/500 winners, regularly seeded at Slams): Pouille, Coric, Khachanov, Medvedev, Donaldson, Kyrgios (as he is now), etc...
Too soon to tell: Aliassime, Moutet, De Minaur, Kuhn, etc
I would add Thiem into the second tier, if we include him as NextGen. There are many others who will be at least third tier, but hard to place at this point and could end up as "fourth tier" non-seeded journeymen (e.g. Fritz, Mmoh, Ruud, Bublik, Kokkinakis, etc).
By the way, I think this second tier will win more Slams than the current second tier, due to peaking in a post-peak Big Four era. Presumably.
But I digress from Roma...