1. Who will win the most titles? Zverev is the obvious choice, given as he's most suited to winning on all surfaces. Medvedev might do more on hard (maybe), but I see Zed picking up a clay title or two.
2. Who wins their first Masters 1000? Sinner or Ruud are great choices. Seeing as they're already said, I'll go with Alcaraz. Maybe we'll see huge improvement from him.
3. Will we see at least one Slam final between Medvedev and Zverev? Seeing as the only places that can happen are the AO and the USO, I'd be wary. If I had to predict a slam final, it would be these 2, but I'm going to say no. I expect they'll meet in a slam SF, and if they meet on opposite sides, someone stops the meeting.
4. Will Cam Norrie win a second M1000? Not a chance. Norrie was lucky to get that, I don't see improvement from here. Maybe he'll become a perennial R16-er though.
5. Can Aslan Karatsev repeat after his breakthrough year? I doubt it. He seems like a streaky sort of player, akin to Stan. I think he'll become a new wildcard in the draw where if he plays out of his mind he could upset a top-4 seed, but in 75%+ of cases, he'll just be a regular person.
6. Will Andrey Rublev be higher ranked than Jannik Sinner by end of year? No, Rublev is falling apart and Sinner's doing fine. Rublev was never super competitive against the top contenders anyhow. Sinner is more interesting to see where he goes, and I expect we'll see a bit of improvement, but not top-5 level yet. Rublev will just fall outside the top 8.
7. Does Tsitsipas maintain a spot in the top 4? Well, I definitely see the current Big 3 (Djokovic, Medvedev, Zverev) staying ahead, so he'd have to be the best of the rest. If he remains healthy, yes. Otherwise, no.
8. Does Felix Auger-Aliassime win his first title (finally)? Yes. He's reaching too many finals to not win one. You'd expect even if his chances are really low in a final, he's still supposed to win one... he'll get it, then it'll start clicking. If he wins his first in the first half of the year, I'll even say he wins 2.
9. Does Matteo Berrettini reach SF at any Grand Slam? If he gets healthy, at Wimbledon.
10. Does someone outside of the big 3 take the top spot at any point in the year? (Name the player) Medvedev.
Explanation:
Federer and Nadal have no chance at #1 anymore. That's over. I also don't find pegging Djokovic for at least 2 slams incredibly likely. He'll lose #1 at some point, definitely.
What I see happening is Medvedev's late season of SF+ at every masters + USO + ATP finals F is a monstrous amount of hoarded points. All he needs is a little slack and he'll take #1 sometime in the early season. Whether that's Djokovic losing AO, or picking up points in IW/Miami, or just grinding out some wins on clay, Medvedev will be ranked #1 by the start of Canada. I predict right after RG, when Djokovic's 2k probably drops somewhat.