Look at Titanfall 2, Call of Duty or even Fortnite. THESE games have aiming mechanics that feel good, smooth and responsive and offer some basic adjustment options that should be standard in any modern shooter (adjust x and y seperetaley, adjust ads sensivity, adjust deadzone)
Problems in D2:
- Deadzones are SO huge (imagine Trump saying this)
- movement is slow as hell
If the gameplay did not feel so weird I would still play D2... D1 felt much better imo