Interesting build and nice guide. I'm one of those WP Vox players I guess you're trying to convince :p

I've tried several CP builds (post 2.0) and to be honest was never satisfied, only thing that piqued my curiosity was a Broken Myth build like this one, only because of how much it buffs Vox's Ult at max stacks. However a Shatterglass is actually much better for the Resonance bounces damage wise than a Broken Myth even at max stacks.

I might try this out to see how it plays, hows the ramp up time? I can only see the effectiveness of this build really kicking in by late game

Generally speaking, it's a very situational build imo. Ultimates have longer cooldowns, what do you do in between? Any other damage you deal will be collateral, and fights usually are not long enough for you to be able to drop your Ult more than once (or twice with Echo). The nature of Resonance requires that enemy heroes be close to one another, and that's provided that you actually hit all your targets, and then there's the situation of running into 1 versus 1 scenarios, in which case you can't do much

But I bet the nuking must be a blast

My big question would be how does this fare in Ranked play?