Grant and Draymond may be a good comp on offense (though Grant still has a ways to go to get there), but I don't like the comp on the defensive end. Don't get me wrong, Grant is a good defender, but he doesn't seem to have the multiple-time DPOY ceiling of Green
At the end of the day, it’s really difficult to project anyone who’s barely played in the NBA as a DPOY. Certainly no one would have projected that for Draymond after his rookie year, and it’s not a big stretch to say that Grant at 21 is equal to or ahead of where a Draymond was at 22. The thing that will define his ceiling will probably be best observed in his foul totals. He’s a very physical and engaged defender, which puts him at risk of fouling when he gets beaten. Draymond averaged 7.6 fouls per 100 in his rookie year and 6.4 his second year, compared to the 3.9-4.2 range for his best seasons. Fouling was a problem Grant had at times in college, and through three games he’s at 6.8 per 100, which (small sample size of course) looks similar to the issues Draymond dealt with early in his career. If he can bring that foul rate down while otherwise playing largely the same style, he might be able to reach similar value on defense to Draymond.
To me there is almost no chance Grant reaches Draymond's level defensively. Draymond has one of the highest defensive basketball IQ's ever, even if you think Grant's is very advanced thats a high bar. Draymond is also significantly longer than Williams.
Draymond comparisons are almost as annoying to me as Durant comparisons. Those guys are freaks in terms of wingspan/basketball IQ. Theres a reason they are DPOY/MVP candidates every year.
Ultimately BBIQ is unquantifiable, so there’s really no good way to have a debate with any agreeable metrics. All I will say is that Grant looks ahead of where Draymond was at similar ages. For one, he is in the NBA 20 months younger. Two, he seems to be more effective than Draymond was in his rookie year — again, only 3 games in and that can change, but Green didn’t even become a member of the rotation until mid-November. Three, I think one stat that can show a hint of defensive BBIQ is offensive fouls drawn. You’re more likely to get those if, as a defender, you’ve anticipated where the offensive player is going and gotten there first. As a rookie, Draymond drew a respectable 7 in a little over 1000 minutes on the court. Through his first three games, Grant already has 3.
Again, BBIQ is virtually unquantifiable, and it’s very possible that Draymond and Grant have/had different trajectories in terms of the development of this skill. But Grant’s already displayed a rare ability, and it would not be impossible for him to be near Draymond’s equal.
let's pick some nits. first, your two bolded statements contradict one another by their premises concerning whether something can be quantified. the first declares it cannot. the second implies it is nearly impossible, or at least exceedingly difficult. these are not the same and the difference between "possible" and "impossible" is significant

next, before we can say whether something can be quantified, we are obliged to FIRST DEFINE the concept. that has not been done here, has it?.
if BBIQ is rendered as a collection of quantifiable categories, such as "number of successful picks + passes - turnovers," then yes, it is indeed quantifiable. but, if your definition is vague, or imprecise, includes non-quantifiable concepts, or is rooted in subjectivity then it becomes unquantifiable.
next, even if the definition can be quantified since it is clearly defined, is the resulting data of any real usefullness? for example, a brilliant and humorous article once spoke of how to quantify holes. first, theorize what is a hole. is something this is NOT there? or is a hole something that is there?

next, having done this we can quantify holes. for example, warfare greatly increases the number of holes. true, but ultimately who gives a crap?
back to BBIQ, add to the above whether all parties share this identical definition for BBIQ. if different parties have different definitions then conversation becomes very difficult as one side talks past the other, even though identical words (but not definitions) are being invoked by each party.
sigh, sigh, sigh...such complications that can flow out of poorly built foundations.
