I question the value of the dip into the Rogue class myself.
I'm very likely biased as I like to actually have some skills other than climb, jump, ride and swim (like balance, listen, spot and some social skills as well). But as you correctly noted, when starting at 1 level this aint much of a warrior build. But already at 2 level that level of barbarian will transform you into a competent warrior only 1 BAB behind the regular ones.
As for sneak attack being situational, sure. But IME it will work in at least 80% of all fights. Thats 2d6 easy extra points of damage on most attacks. I'll wager that it beats weapon specialisation in the long run in most campaigns.
Feats. Well nothing prevents you from taking Power attack and Cleave. Two feats that any warrior will want along the way.
To me those 4 levels of Rogue just cant be beat.
Going by standard array it will be something like this
Human rogue1
Str: 15
Dex: 13
Con: 14
Int: 10
Wis: 12
Cha: 8
HP: 8
AC: 14 (std. leather)
Move: 30 ft.
Fort +2, Refl +3, Will +1
Attack: Longspear +2 (1d8+3) or light crossbow +1 (1d6); sneak attack +1d6
Skills: Balance +5, Bluff +3, Climb +6, Jump +6, Listen +5, Search +4, Sense Motive +5, Spot +5, Swim +6
Feats: Power Attack, Cleave
Human rogue1/barbarian1
Str: 15
Dex: 13
Con: 14
Int: 10
Wis: 12
Cha: 8
HP: 16
AC: 15 (chain shirt)
Move: 40 ft.
Fort +4, Refl +3, Will +1
Attack: Greatsword +3 (2d6+3) or light crossbow +1 (1d6); sneak attack +1d6
Skills: Balance +5, Bluff +3, Climb +7, Jump +6, Listen +6, Ride +3, Search +4, Sense Motive +5, Spot +5, Swim +7
Feats: Power Attack, Cleave
Raging
HP: 20
AC 13
Attack Greatsword +5 (2d6+6); sneak attack +1d6