From a pure basketball skill set, he's better than Pierce but I'm not ranking him over Pierce yet. I've said it before, he has the highest ceiling since Bird.
He has the potential to retire as a top 5 Boston Celtic ever.
Will he get there? No idea but I hope so because that means more championships.
This feels right. On a purely 'vibes-based' basis, I think it goes something like this:
The absolute top of the mountain: Pierce, KG, McHale, Bird, Cowens, Russell. Guys like that.
The next rung: Tatum, Allen, Rondo, Parish, Ced, DJ, Heinsohn, Cousy, &c.
My 'very deep' thought process, looking at our championship squads.
From the last championship/contending core:
I would put him in line with, say, Ray & Rondo, and a wee bit behind Pierce and KG.
From The Bird-cores: He's behind McHale, Bird, and Walton (only if we're including Walton's peak - his time in Portland). On the level with Parish, Cedric Maxwell & DJ.
From the 70's he's behind Cowens and... that's it.
I'm certainly not rating him against Bill but I would take Tatum over anyone else on the Russell Dynasty C's.