First of all, 40 yard dash is irrelevant in my opinion. There won't be, ever, in the NFL, 40 yards between the pass rusher and QB. If your pass rusher is 40 yards in pursuit thats not good news.
Where Bosa really opened my eyes, his 3 cones drills and 20 yards shuttle. He was a WOW. Posting same numbers as JJ Watt and I mean.... same numbers
3 cones :
Watt (290) : 6,88
Bosa (269): 6,89
Clowney (266) : 7,27
20 Yards shuttle:
Watt (290): 4,21
Bosa (269) : 4,21
Clowney (266) : 4,43
The only thing, Watt was 290 and Bosa 270. So let's compare Bosa with others 270 players : Dodd and Lawson. He destroyed them in both drills. He was also a lot better than Floyd whos 244. Von Miller drills were a lot better than Floyd at the same weight.
At the end of the day, the reason why I think Bosa won't end up with 12+ sacks is because he doesnt bend that much. Which means he'll be better when pass rushing from the inside on 3rd downs so he'll probably face double team blocks. I still don't get the hate on Bosa. He's a freak specimen and he"s one of the best with his hands I've seen. The guy will be a pro bowler but I still think he would be better in a 4-3 scheme. Thats why I talked about the hybrid like the Ravens did with Suggs