I actually want to direct this @
Shadowpunkz
I know you said you are a noob DH, but I wanted to let you know a lot has changed since 7.1.5.
you mentioned Throw Glaive and Bloodlet being your 3rd most damaging spell...I would suggest you change to First Blood instead of Bloodlet and put Blade Dance/Death Sweep as your #1 priority ability regardless of number of enemies. you should see a noticeable difference immediately.
Also you mentioned Fel Rush...unless you take Momentum (which you shouldn't) Fel Rush is lower on our priority list now. It is basically "try to keep it off 2 charges"
The "cookie cutter" raid spec now is Felblade, Demon Blades, First Blood, <your choice...I like Netherwalk>, Nemesis, The Glaive one, Chaos Blades
Again, not trying to rip on you, it just sounds like you might be running on 7.1's information and wanted to let you know it's been updated
Cheers!