Total tackles is hardly a stat dependent on one players instincts or a window into what he will do in the NFL. And do not compare him to kuechly, thats just ridiculous.
He's undersized
Bad instincts IMO, and in many scouting reports
Constantly over pursues
Can't shed a block for his life
Doesn't show anything special in coverage
No physicality
Everyone talks about how "special" shazier is, but almost never hear anyone say what he's actually good at. Just, OMG he's so explosive.
If you don't think 102 SOLO tackles is impressive, we're not going to agree on much.
I disagree with all of your trait evaluations to varying degrees.
Look at the combine weights of the best 4-3 OLB's and 3-4 ILB's over the last 10 seasons. He's bigger than many of the best, and even if you go back to Ray Lewis, he entered the NFL at right around 240. He's bigger than guys like Timmons, Washington, David.
He has elite instincts around the LOS. As I said, he's one of the best LB's at shooting the gap I've ever seen. His instincts in space are a plus, but they're not as good. As a total package, his instincts are very good. And given his limited time at LB, there's still room for growth in that area.
It's a huge exaggeration to say that he constantly over pursues. A player that makes 23.5 TFL is going to do it from time to time, and he does from time to time. But he makes the right read much more often than the wrong read. Again, hard to get 102 solo tackles (144 total, btw) when you're constantly guessing wrong.
For a WLB, he's great at shedding blocks. You're not asking him to line up over the TE. But Shazier dealt with more O-lineman than any WLB that I can remember, and he was very productive in games where he was forced to deal with O-linemen play after play (see Michigan State).
He had 10 PBU's as a Sophomore in addition to a pick-6. He played more around the LOS as a junior, but he can cover (especially in man), and he has crazy range. And if he's man on your RB, you better get that RB into a pattern, because he'll kill your QB.
To say that he shows no physicality . . . how much have you watched? He's a violent LB.
If you're paying attention (like to the post I just made), you'll read what he does well. Again, he has elite instincts around the LOS. Shoots gaps as well as anyone. He has the most insane closing speed I've ever seen from a LB. He can be playing 5 yards off the RB in man coverage, and in the blink of an eye, he's hitting the QB. He makes driving killing plays (7 sacks, 23.5 TFL, 4 FF), and he makes big-play-saving plays (102) solo tackles. His range is unreal.
Your description fits a collegiate LB barely making it. I'm doing my best, but I can't think of another season where a player had 20+ TFL and 100+ solo tackles. If someone knows the list off hand or has access to it, I'd be interested in knowing its other members.
I know he's no Bishop Sankey, but give the guy a break.