Darius' Q radius nerf is in the wrong direction
Disclaimer: I am a long time fan of Darius and happy to see him not being a troll pick anymore, but he does need to be addressed
I understand what you're trying to do, keeping the massive damage if he lands it but making it easier to avoid so that he has more peaks and troughs in his power.
Now to my understanding, this is just increasing the length of the "handle" while keeping the range the same, but what you should be doing is looking at the base damage buff you gave it originally. For how much he scales he trades too hard early without Noxian Might due to those numbers
Every champion needs a certain amount of reliability, and instead of lowering his power in general you're only making him weaker against mobile melees that can stay in the inner circle. He'll still shit on immobile melees because they get slowed and can't dodge the blade
I think the Apprehend slow nerf is fine, but consider lowering his Q base damage to 130 or 120 instead of 160, possibly even lower if you make Noxian Might give more AD or increase the total AD scaling slightly
Edit: First post is incorrect, large champions can already fit inside the Q