Is it me, or is DRK really isn't that super great, nor super bad.

[Gooner_iBluAirJGR]

Fel Cleave only costs 5 Stacks Abandon. . .

Only 5 stacks lol. All of our moves that consume Wrath/Abandon cost 5 stacks and Fell Cleave (in my experience) isn't always the go to move to consume those stacks (when main tanking). If we use fell cleave we can't use Inner Beast / Unchained until we build the stacks back. Without blowing cooldowns (Berserk, Vengence and the new skill Raw Intuition) it takes 8 GCD's to build 5 stacks. The damage is great but its got its own set of pros and cons.

p.s. in order to use Fell Cleave we have to switch Defiance for Delieverance which reduces our max HP and removes our Healing received buff.