I'm impressed with what he's accomplished so far this season. I've always found 15 and 5 to be decent numbers for an upcoming talent, 17 and 7 (my preference) for an all-star level point guard, and 20 and 10 to be superstar level. 19 and 8 is pretty decent as a point guard. The fact that he looks like one is a good sign. The ability to shoot also doesn't hurt. If he got to Mark Price-level (1989-1993), I'd be more than satisfied (just need him to stay healthy, *knock on wood*).
The problem will be sharing the lineup with another short guard. As mentioned in the Sexton thread, we've had two short, but high potential guards on the team coming into their own at the same time: Price/KJ in 1987, Brandon/Price in 1993, and Andre Miller/Brevin Knight in 2000. Same issue each time: Pick 1 guy to build with, trade the other. Now don't get my wrong, sometimes it changes the fortune of a team to get over the bump (like getting the original Larry Nance)... but it doesn't always go smoothly. Can they co-exist past this building year and become more? Need a bigger sample size. Maybe we'll know closer to February. But I love having these types of problems (rather than having no talent at all).