The hype. I think he is going to get exposed once he hits top level competition, just as Lacy did. Unless he drastically improves, which he probably wont.
Lacy was speed and power. Anyone who goes toe to toe with him will lose, etc.
Same thing with Gamboa. Too fast, a ton of power, etc.
Yet they both have horrendous defenses, get hit a ton, and more credit due to Lacy he hasn't been down as much as Gamboa has. Once you start facing top tier opponents you need to bring a lot more to the table than that. He needs more craft.
Not saying its a for sure thing, just saying it looks like he is on the same path as Lacy. They need to move him along slowly, which they are doing.
Even though he is ranked 4th, he has only fought 1 fighter who was even ranked in the top 20. Which was last night.