They are better than most other base classes yes; but since most of them (including monk and CWar Samurai the "weakest" melee clasess) have a niche thae ToB can't fully replace they aren't completely obsoleted by them.

One example is Fear Stacking, somthing that the Samurai shines at, or even at RAW damage. A properly built barbarian will outdamage a similarly tricked Warblade. Their biggest draw is their versatility which gives them something to do out of combat and contribute in combat without the "I full attack... again" problem of most martial classes.