let me give you some numbers, my barb is at 32 str (18+4+3+1+6), my fighter is at 35 str (18+4+3+1+3+6), so their mods are +11 and +12 respectively. lets do damage calculations
the barb can rage for 10 more str, 32 becomes 42 (+16). barbs have PA enhancements (+3). not counting songs and other buffs, a 1 handed weapon barb will be at 16+8(PA)+5(weapon) = +29 damage. the fighter will have specialisation feats which put him at 12+5(PA)+4(specialisations)+5(weapon) = +26 damage. this number is not significant as pre mod6, DPS is defined with 2HF
a 2HF barb will do 24+16+5 = +45 damage, a 2HF fighter will do 18+10+4+5 = +37 damage. comparing both styles, regardless of the presence of crit rage 2, the barb IS more DPS than the fighter. the addition of crit rage in mod 6 further enhances the role of the barb as the DPS toon, so much so that fighters and paladins are made redundant. not sure about you but the barbarians i run with are not as gimped as the ones you run with
last but not least, fighter weapon specialisation enhancements came in MOD EIGHT. you ARE comparing a post mod 6 barb to a mod 8 fighter. get your facts right