What race is this Barbter? (Fightarian?) If Human, there are some great low grabs in that tree. HOrc (if 2 handed) or Dwarf (if Axe), too.
http://ddowiki.com/page/Human_enhancements
And what Feats does he have? If Stun, then it might be good to improve Sneak Attack.
If, otoh, you took the Rogue dip just for solo trapping, would a little Mech help to get/keep some of that up to Elite levels?
If he uses axes, why? (Unless bugged???)
Instead, with 4 AP consider something like one (or more) of...
o 2 Ken T IV: Weapon Group Specialization:: +1/+2 w/ two-handed weapons! (~IF~ he has Greater Weapon Focus feat)
o 1-3 FB T III: Blood Trail: less HP cost for Supreme Cleave (-10/use by default, costs -7, -4, -0).
o 1-3 AP FB T II: Blood Tribute: 1/2/3 AP for +50/100/200 HP and -1/2/3 Con for 1 minute. Perfect for a late-battle self-heal before the win.
o 1 AP Rav T III: Aura of Fear: All nearby (read "anyone trying to melee you, or that you're melee'ing") lose -2 St (and -2 Cha), that's -1/-1 (and you're no friend to Sorcerers etc.) Another 1 AP adds -2 Dex, reducing AC (and Ref ST, and etc.) & -2 Wis (for them evil cleric types). Better at lower levels than endgame, admittedly.
o 1-3 AP Rav Tr III: Slaughter: 1/2/3 AP for +(5/7.5/10)[W] attack. 30 sec cooldown, but wow - with a d12 graxe, that's +65 damage boost right now. o.O
o 1 AP FB Tr II: +35% Sprint Boost for 20 seconds - close the distance (or increase it!) NOW.
(And maybe I'm missing the obvious, but I'm also no big fan of 3 AP into Hardy Rage - +Con while Raging? +6 seconds Rage, a few more temp HP and +1 Fort ST? Meh. Nice, but with 8 Rages and a LOT of full-time AP beni's for the mobs, there are better things out there imo.)