I still think FAA will jump a couple steps forward - go back to where he was in 2022 and then take another step forward from there, and at least more firmly join the Rublev/Ruud/Hurkacz coterie, and maybe half a step up to Zverev/Tsitsipas in the "lesser elite" category.
Tiafoe is weird, because he has a few people who believe he's a potential elite. I see him as a potential...well, "tier 2.5" type ala Gasquet/Monfils...not quite a true 2nd tier guy, but will be around the top 10-20 range, maybe dip into the top 10 a bit. I mean the guy is almost 26 and has just lightly fondled the top 10. He's had a few matches here and there where he looked really good, but I just don't see him getting significantly better. Could be wrong, though. Still, he's the type of player who, in a "weak era" (e.g. late 90s, early 00s) might have won a Masters. Look at the list of Masters winners back then...lots of guys who would have maxed out at ATP 500s today, if that.
Shelton looks good, but it is too soon to say where he'll end up. He could be a future lesser elite or Jerzy Janowicz. And I find him kind of annoying, so he's a guy I'll probably root against. Seems a lock for the top 10, though, and I think should be at least in the Rublev/Hurkacz group, maybe in the Zverev/Tsitsipas category. Fils is a guy that I hope could be really good, like maybe even in the Alcaraz/Rune/Sinner range. But I'm probably getting ahead of myself.
Anyhow, I do feel that the talent level is rising overall, at least among players debuting over the last 15 years or so. Next Genners are better than Lost Gen, and Millenials are better than Next Gen. So tennis is going in a good direction. While Next Gen didn't give us any true ATGs, there are several guys who are as good or better than any of Lost Gen -- Thiem (the first Next Genner), Medvedev (the best Next Genner), Zverev, Tsitsipas, Rublev, Hurkacz, maybe one or two others. And Millenials have a handful of guys who could be even better than most of those guys - Alcaraz is already there, Rune and Sinner are getting there, FAA remains a darkhorse, plus Shelton, Fils, etc.
As for Rune, I still hold to the view I expressed late last year...I see an explosive player who will have spells in which he's virtually unbeatable, and even peaking a bit higher than Alcaraz for spells, but being far less consistent. Sinner will be right there with them, although maybe a sliver behind.