I expect him to be as good as Clay Thompson. Seriously.
I was just comparing their measurements on draftexpress and was surprised how well RJ compares to Klay.
Height w/out shoes: RJ 6'4.5", Klay 6'5.75"
Height with shoes: RJ 6'6", Klay 6'7.25"
Weight: RJ 185, Klay 206
Wingspan: RJ 6'10.5, Klay 6'9"
Standing reach: RJ 8'8", Klay 8'7.5"
No step vert: RJ 27.5", Klay 26.5"
Max vert: RJ 33.5", Klay 31.5"
Max ver reach: RJ 11'5.5", Klay 11'3"
Agility: RJ 10.97, Klay 10.99
Sprint: RJ 3.26, Klay 3.24
While Klay is an inch taller, RJ makes up for that with longer arms.
Klay does have 20 pounds on RJ, but just a year before the combine after his sophomore season, Klay only weighed 190. He put on 15 pounds during his junior year of college just a year younger than RJ is now. In the NBA training program, there is no reason Hunter couldn't put on 15 pounds over the next year.
Their athleticism is very comparable.
Their college stats are very similar across the board. RJ's 3 point shooting was down his junior year, but I think it's understood that is not an accurate reflection of his shooting ability.
At first I scoffed at the Klay Thompson comparison, but it could be fairly accurate.
RJ was raised by a coach, has a high basketball IQ, and supposedly has an excellent work ethic. It would be outstanding if he reaches Thompson's level and it might not be too far fetched.
It's worth noting that not a heck of a lot was expected out of Klay Thompson. Part of the reason for that is that the physical profile above is not at all impressive. It's misleading to frame traits as strengths just because they are shared with a good player. Isaiah Thomas is a good player, but I'd be feeding you a line if I picked out any short-stack in college that can shoot and told you it wasn't far fetched that they could be like him.
What? 6'6", 33" inch vertical, and 6'10" wingspan physical profile with that shooting ability isn't impressive? The only thing truly unimpressive about Hunter's physical profile is his weight, but if he can get to 200-210 over the next few years (which is certainly possible), he is basically the prototypical SG build.
I'd argue about Klay Thompson also. He was chosen in the lottery. All lottery picks have a certain expectation about them so saying no one expected anything out of him is false.