Without SS active:
The problem is I don't really have a good feel for what kind of trade-off is worth it in terms of trading pure DPS for Dex/crit basically.
Well I'd love to help on a general case for it but ... there isn't one.
(Weapon DPS / Base Attacks Per Second) * (Actual Attacks Per Second) * (1 + DEX/100) * (1 + CritChance*CritDamage)
So:
788.2 DPS Weapon 1.10 Attacks Per Second base with 2067 DEX, 1.87 actual Attacks Per Second, 8% Chance to Crit and 150% Crit Damage:
(788.2 / 1.10) * (1.87) * (1 + 2067/100) * (1 + 8% * 150%)
~= 32,520 DPS
So, let's do your new Weapon which is 931.2 DPS, same Attack Speed, -61 DEX, -50% Crit Damage:
(931.2 / 1.10) * (1.87) * (1 + 2006 / 100) * (1 + 8% * 100%)
~= 36,006 DPS
Edit: Or the one you just bought which is 915.2 DPS and +17 DEX over the original but still -50% Crit Damage:
(915.2 / 1.10) * (1.87) * (1 + 2084/100) * (1 + 8% * 100%)
~= 36,698 DPS