No one is right or wrong on Tamar yet.
If he continues to shoot the ball well, he'll establish himself as a "plus" shooter in NBA GMs eyes. They're looking for really tall 3 and D guys right now, more than anything. So his size will probably hinder him, no matter how elite of a shooter he makes himself in their eyes. But if he shows he can adequately defend, handle the ball, distribute...AND is an upper end shooter...he'll probably get some looks at some point.
I don't follow Mizzou, so I don't know if the offense they run is completely different to IUs, or not? But assuming it is, and assuming it is much more conducive to guards getting good shots in rhythm...the stark difference in his play at IU, and then his play at Mizzou...might actually hurt him in some GM's eyes.
JHS stock rose like it did, I'm guessing, because he was consistently impactful and productive in an offense that did little to nothing to help him produce. He proved he's a guy that can manufacture points and plays on his own. Tamar didn't prove that, at IU. And he might not be proving that now at Mizzou either?
Regardless of all this...I wish no ill will towards Bates...hope he continues his great play. If nothing else, it'll be a glaring example of a guy Woody "missed" on because of the style of play he chose, and has now double and tripled down on.