A good role playing game offers a lot of versatile content; if the thief who sucks at combat feels like a dead weight to your party then the content simply isn't designed properly. The reason games like Dragon Age and MMOs have molded rogues into a damage dealing combat role is the fact that there isn't any content besides combat in those games. Exploration, Sneaking type quests, secret areas, tricky locks that lead to greater treasure, situations where you need that silver tongued rogue should be plentiful.
The only way to make rogues interesting is to design enough content for them, no amount of dual wielding combat badassery is going to do that. I say that if you want to be a dual wielding finesse fighter, roll a fighter, not a thief.
It's easy to make rogues more useful by adding secret passages and ambush points. You might start an encounter by charging in with your fighters while your thieves flank the enemy. You might encounter an enemy camp full of sleeping bandits, and now it's time for that thief of yours to slit some throats, lay some traps and maybe misplace a few of the bandits' armaments. Maybe cause a distraction by setting the enemy horses loose and scaring them away, start a fire so that your party can attack a confused enemy.
EDIT: ok, maybe it's not easy to script but it's the only real way that works.
Just think outside the box and forget direct combat and you'll find lots of ways to make rogues both interesting and valuable party members.