It simply would add options. Players could add SkS such that they would know they cant weave post 1.5 gcd standard skill, and if they do well they just havent gotten the full benefit of the substat (weave). And the SkS scaling could be proportionally smaller just as it is proportionally bigger with longer gcd skills. There is almost no reason not to do this. SkS would at maximum take maybe .1 off the .5 gcd anyways. I mean who stacks enough SkS to go frome 2.5 to 2 flat anyways? (1/5 proportional) These skills could still be untouched by haste (like gl, or huton) if needed, or have their base speed set such that with huton or gl 4 its .5