One major gripe I have with Brad this season is that he hasn't been utilising Brown all that well. It was common this year to see him have a huge quarter of feeding off of scraps (and he'll get a few possessions on the ball because teammates sense that he's hot) and proceed to stand in the corner the next 1-2 quarters in a way that almost looks instructed. This wasn't even because Tatum and Kemba were in front of him in the pecking order - we could have Smart, Teague or FastPP out there and they can still be running PnRs over and over while Jaylen is either in the corner or at the wing as an emergency bailout isolation scorer.
I wonder, though, how your observations played out over the course of the season. There were definitely plays where Jaylin ended up in the corner, but I doubt it happened as much as you think it did. JB put up over 19 FGAs per game, so he definitely got significant touches. (Tatum ranks eighth in the NBA in front court touches; Jaylen is 22nd.). He was also extremely efficient per touch, which leads me to believe he was used mostly properly.
That was where my 'feeding off of scraps' comment is relevant - Jaylen found ways to score and create in spite of his role on the team by being a freight train in transition, a deadly catch and shoot scorer, making the most of his bailout isolation possessions, etc. A high efficiency per touch can definitely imply that a player is being used in an optimal role, but in Jaylen's case I see a player who's so good that he made a sub-optimal role look like an optimal one, and there's always the argument that a guy who's so efficient in a limited role should get an opportunity to play in an expanded role considering that Jaylen is a pretty skilled player from the eye test.
To expand on this now that the season is over:
PnR Ball Handler

Isolation

Post up

The Celtics use him quite a bit in handoffs and off screens (he's surprisingly terrible at the latter, but this can be somewhat explained from the mini-scouting report I wrote above - some of his possessions where he's required to bail the team out comes from him running off a screen from the corner/wing and catching the ball to do something magical with it in a few seconds, which is pretty much setting him up to fail). But my general point stands: Brad has been doing a terrible job at utilising an athletic wing with an explosive dribble drive game, accurate shooting from all three levels of the floor as well as a strong post game by sticking him to a stationary off-ball role with some handoff and screen action (which isn't inherently bad as both of these theoretically give him a runway to the basket or an open shot, but it's a problem when they constitute the bulk of his offence + one of them being used mostly when the team needs him to bail them out instead of being a regular thing we run in our sets).
Love the analysis. TP.
Question; in your opinion, how close are Brown and Tatum? I'm curious if we could swap their roles. How Brown would do if he was the go-to instead of Tatum.
I think both are closer than what their current stats (box and non-box) suggest: I view Brown as a top 20-30 player if utilised correctly (his quick-hitting skillset brings little to no opportunity cost to talented teammates, so there's no excuse to not consider his value in an optimal role) while Tatum is a top 15-20 player who can challenge for an All-NBA team. But Brown's optimal role isn't an on-ball star like Tatum currently is for the Celtics: he's a wing who alternates on and off the ball with minimal time of touch but still devastate defences with drives/shooting/post ups and solid passing, kind of like a Butler/Middleton hybrid without the elite wing passing as well as composure/ballhandling in tight quarters.
This is where I think we can reasonably call for Brad's sacking: instead of moving to a more egalitarian system when we had success with a more balanced system last season that sputtered when we moved away from it in the playoffs, we shifted to a heliocentric one around a guy who's not good enough to lead teams to titles in that role that stunted the growth of one of our young stars with
no immediate results to justify stagnating Jaylen's growth. People might argue that we're putting all of our eggs into a Tatum-sized basket, but we can develop Tatum in an on-ball role without marginalising Brown while having better results than the crap we've been served this year!