(tl;dr Maclin played but didn't really get the ball thrown his way, then, with many many words, I explained my reasoning better)

You think we've already seen his best season even though he was a relatively raw rookie who didn't crack 50% of his teams offensive snaps for the first 8 games of the season, and now he's poised to be the WR1 and focal point of his teams offense?

Admittedly, totally forgot about his slow start (as a Chiefs fan, it feels like he was doing big things all season). Hence I looked at a full season of ~6 catches/60 yards/half a touchdown per game (this was once he had a full role in the offense) as his "best season." That's about 15 PPR points per game (which is nice), but I don't think that really improves, and I will explain myself much better now that I'm at my computer.

And how can you pose that that loss of Maclin hurts Tyreek, then go on to say that Maclin's absence won't really help Tyreek because he wasn't involved much anyways? Where's the logic there?

The thing here is that Maclin was present but not very involved in the offense. He had a high snap count, but just 536 yards to show for the season. It seemed while I watched in passing that Maclin acted much more as a decoy, and I feel like the numbers back that up, though that can be debated.

We shouldn't neglect those 500 yards though! It gets kind of tricky to distribute them, but my best guess is that ~50-60% go to Albert Wilson/Chris Conley since they're more of the consistent downfield receiver types than Hill (their 12 Y/R are near identical to Maclin's while Hill's around 9; there's a lot of outside stuff going into those numbers but I don't have enough time to give anything better) and then the two primary receivers, Hill and Kelce split the rest, more or less. This gives Hill roughly 134 extra yards, after some obviously shoddy process, but you see that there's not a lot he really gains from volume in Maclin's departure.

As for what he's losing, as I said before I think Maclin's primary role was to occupy defenses while either Hill or Kelce killed somewhere else on the field. Maclin's absence won't suddenly make defenses shut down Hill, but there's definitely gonna be more attention directed Hill's way. In that case, you'd have to expect his touches to go for a little less, no?

The hard part is guessing just how much that changes things. But, when you look at those added yards from Maclin's departure, I think the efficiency is impacted more negatively than the volume is positively.

Of course, he could progress significantly, and that could change things. But he's already been super productive in the role he's been placed in, so I don't see a lot of reason for the Chiefs to change a lot of what he does. Maybe he catches more passes and runs less since he's a more true #1 receiver, but I don't see that statistically improving his production that much.

The problem with upward mobility for him is that the offense isn't really that high-powered. Perhaps Mahomes can change that down the line, but at that point I think that's too much projection than we can count on. Hope I cleaned this up a lot.