Gallo has heart and confidence since day one. He thinks like a winner and understands the game well. He has surprised me this year at times, defending pretty tough players well one on one. He has also been made to look foolish plenty of times.
I agree that there's tweener aspect to him that puts him in tough matchups sometimes. But it's the NBA. Happens all the time.
I always saw him as mentally tough. Wants the shot and hits, often in crunch time or at a critical moment. Hasn't been aggressive enough, demanding the ball.
A month or so ago I would have said no doubt, he will develop into a second tier star eventually, barring injury etc. But he has wilted lately, looking timid even. So we'll see. I do believe the potential upside is very big, but in no way guaranteed.