Was his original CDR ratio 1.5% AS for 1% CDR?
If that's the case his on-release maximum bonus was 60% AS. Stinger and Nashor were both giving 50%.
60+50=/=130
His on release DPS AP ratio with Stinger and 40% CDR: 0,8085
His post passive nerf on release DPS AP ratio with Stinger and 40% CDR: 0,77
His current DPS AP ratio with Stinger and maxed W: 0,7875
That's a net 2.1% AP ratio nerf compared to his release state, but a 1,75% AP buff compared to his later nerfs.
Literally unplayable.
Of course I won't cover the significance of nerfing and later, removing the CDR->AS conversion on his passive for his early game, because he was and basically still is an incredible toxic lane bully.
Edit: Further research revealed Azir actually had 50% AS from his passive, instead of 60% as I previously thought.