[Hessah]

What's Concussive Charge? Is that the single target stun skill? If it is.. then there's no need to empower that... you won't be using that skill once you've got devestate (I believe they share the same cool down, so you can use one after another..)

I think PVP players use axe.. so you'd want to power up your Power Hit..

I've never tried dex on a fighter so I can't comment on that..

Definitely cool down and power up for Devestate..

SP consumption is up to you.. fighters have a low SP pool and cannot carry that many SP stones.. so you'll find that you'll run out fairly quickly.. it just means you've gotta go and restock more often.. or carry SP pots..