Advice for my shaman? He's kinda gimpy!

[Saker]

I have a barb shaman, loved playing a troll shamn back-in-the-day and didn't feel he was gimpy, but the barb shaman I have now, definitely feelin gimpy.

here are his stats and items, advice on what's the problem. Know that high level purchases are out of the question. But I must have some serious weaknesses that I'm missing...

barb shaman level 18
his own buffs
HP 407
mana 433
end 411
ac 412
atk 383

chitin shell armor
bone legplates
banded mantle
banded boots
guard bracelet
large ringmail bracelet
cracked darkwood shield
ykeshan war club
banded cloak
banded mask
turtleshell helm
initiate symbol of the tribunal