Not that I expect you to have greater banes and slayer arrows on 100% of the time, but they're pretty much required in a boss-beatdown scenario to remain competitive when manyshot is down.
20 Starting Str +3 levels +6 item +2 rage potion +6 Rage Str +2 ship buff +2 frenzy +2 horc enhancements +1 horc power rage +4 barb power rage
= 48 Str (+19 mod)
+5 Flaming Burst Greataxe of Pure Good
1d12 +5 enhancement +28 Str + 10 Power Attack +4 Horc PA +6 Barb PA +4 Orcish Melee Dmg = 63.5 base damage/swing
Give him bloodstone too. Note that Frenzied Berserker 2 gives him +1 crit multiplier on rolls of 19-20.
Miss (1): 0
Hit (2-18): 63.5 + 1d6 flaming +1d6 pure good +2d6 frenzy = 77.5
Crit (19-20): 254 + 24 bloodstone +1d6 flaming +1d6 pure good +2d6 frenzy +2d10 flaming burst = 303
That's 96.175 damage per swing.
At 12 we'll give him just THF, no iTHF or gTHF. That's 30% base damage, 7% special procs, on 2/4 swings.
19*(63.5*0.3 +2d6*0.07 + 2d6)*0.5/20
So that's an average of almost 109 damage per swing. At a hasted attack speed (99 attacks per 60 seconds) that's almost 180 DPS.
But keep in mind that your single target DPS will always be much lower than a melee toon, and so when DPS truly matters, like beating down Horoth or finishing off an enraged Lailat, you'll be a liability in comparison to other toons.