I think it might be fair to say that both players (Smart and Brown may be at fault for different reasons).
Marcus Smart:
A hot headed player who plays at a 110% KG level intensity at all times. Makes some stupid offensive choices more often than we'd like- obvioulsy incredible defensive player. I'll also say this - if the rest of this team, and PARTICULARLY Jaylen Brown, played with the physical intensity Smart plays with, we would be up 2-0 right now, no question. They don't, particularly Jaylen Brown. Marcus Smart, in the best of ways is street brawler basketball player in the mold of Rodman, Draymond, KG, etc., and I'll take him every day of the week in games that matter.
Jaylen Brown:
Uber athletic player who is an intellectual with marginal BBQ IQ. He's a beast of an athlete, who, if he again played with the physical intensity of Marcus Smart, would already be an all star. But he doesn't, he plays like a disengaged Chihuahua way more often than would be acceptable for meas a coach. He drifts, he's gets moved around in the paint when he shouldn't. He rarely, if ever, truly imposes his physical will on anybody for sustained periods of time. Basically, he's a passive player for the most part. Jaylen Brown playing with consistent physical force and maximum effort on a consistent basis would most likely propel us to a banner this year. What he does is simply not "good enough" given the tools he has.
He could really use a coach like Popovich or Phil Jackson to be way up his backside on a daily basis to reach his potential. He's probably a product of his environment, like us all. He grew up in a privileged environment, unlike guys like Wade, Smart, Butler, Bird, etc. And he doesn't have a natural killer instinct - and it's hard to teach that. He has to be driven their, again by a coach that will truly challenge who he "thinks" he is.
For me he's way too cool on the court - he needs "way more grit" than he currently possesses and/or displays. He's sorely deficient in both motor and grit. He should be mauling guys nightly - but again he's often in chihuahua mode...
Smart probably gets into him for that. They're a little bit like oil and water. Street brawler versus the intellectual.
We'll see how they work it out - we need both guys.
I was hard on Jaylen just now. I really do like him as a player for us long term but he constantly keeps me wishing for more than he delivers - and it's solely about grit, heart and motor - if he adopts Smart's tenacity we'll probably win multiple titles with him and Tatum. If he doesn't, titles are unclear to me.