iv played sin, barb and demo at 80
few tweaks could be made to better balance the barb
for instance, devastation with 5 pts in its gives 1% crit chance per stack, which procs at about 20% of the time.
savage rage has a maximal stack of 3 times for a total of 6% dmg increase with a 15 sec cd, with my barb's 12.9% crit chance it is both unlikely to proc it if u land a sequence of clobber; wreck armor;(not specced) and whirlwind, but the dmg boost is very week.
this coupled with the other crit ratings in reaver tree the bonus in hitting these single crits is not there, the reasoning to increase your your dmg by 5% per stack when your 2 stacks worth 10% dmg is about to expire would make sense