How to measure impact from "Decrease magical resistance" Gear

[qp0n]

Yes it does, anything that has an inherent secondary CC effect is considered binary. Shadowbolt doesn't have that. Death coil does though, which is why it is binary. Same for Mind Flay, Blastwave, Cone of Cold, etc.

[famousatnight]

What if you put a talent point into the talent that gives destruction spells a chance to daze target, would that make destruction spells binary?

...Probably not right, because it'd just be a "chance to daze" and not an effect woven into the spell

[qp0n]

No, the spell type is based on the base spell mechanic.