I’m working on my NF covenant stuff and I have the NF legendary. Should I be using Faeline Stomp on CD or should I be maximizing the uptime on the 8% dmg debuff? Faeline Stomp by itself feels lackluster for ST. 
As what spec? Also of it feels lacklustre for st, it’s because it is 
I think you just use it on cooldown.
Generally you want to keep it up about all the time. If a global is free, it’s off CD, and you don’t have a priority ability to use, just toss it. 8% amp is awlays nice to have down. And yes, it sucks ST. It’s a cleave build.
I just used it on cooldown, it’s a little better with the legendary but eventually I got bored with it and nightfae in general so I switched to kyrian and I’m bored with weapons of order as well so I’m debating on either necrolord or revendreth currently
I think you’ll love Bonedust Brew.
I realized today that Faeline Stomp with the covenant legendary super charges Grove Invigoration, so Faeline Stomp might not do a lot of ST dmg by itself, but it buffs the crap out of your other abilities.
One thing you have to remember, the faeline stomp/Niya interaction is something that has its own internal CD.
The stacks you get from it don’t stack and stay, they drop off after every 30 second window for each one you use. It’s tragic because that’d really help NF out if it didn’t have those internal timers.
They overlap, though. I’ve gotten up to like 18 stacks. Even with all those interactions, it’s still not nearly as good as Bonedust Brew.
Yeah they overlap, but internal CDs make it rough.