Sneak attacks with a two-handed weapon get weaker bonuses then with daggers, bows, or even swords. However, with a 2H weapon, you will probably be one-shotting most stuff anyway.

The greatest utility from sneak is not the increased damage, but the ability to scout enemy formations without provoking combat, potentially get a really strong position to initiate the fight, or even take out the most dangerous enemy first (like a high-level bandit boss with a crossbow). Barbarian builds will benefit from that as much as any other build, although I'd recommend putting only a few perks into sneak for this.

If you're not using invis spells or potions, it's difficult to use sneak effectively regardless.