Confirmed Stability has no effect on Critical aiming time. I have it up to 2seconds through skills on AR, and with a maxed out stability 3-star Samael AR, it still takes.....2 seconds.
Scorpion--where does damage fit into your equation there? Noticed you left it out.
Are some stats more important for some weapons than others? For example, I would assume recoil to be a bigger factor with SMG's than accuracy since it's a volume of fire weapon.