There is nothing incredibly good about Versatile Duelist. It sounds super good until you actually look closely. The feat itself does nothing for you that Rapier Proficiency doesn't do. All it does is let you use a longsword (+3/1d8) vs a Rapier (+3/1d8). You can then spend ANOTHER feat and use a bastard sword (+3/1d10). Contrast this with spending another feat to make your Rapier +4/1d8 instead and you find that the rapier path is actually marginally superior. Most of the heavy blade feats you can now open up aren't really all that exciting for rogues either. HBO for instance may be somewhat useful but not earth shaking for a rogue and is unusable by a thief.
Basically there are no feats that will give a rogue a superior option to a dagger. Any feat chain you follow ends up with the rogue using a weapon slightly better than the dagger, but not better than the dagger will be if the same feats are used to buff the dagger instead. So a rapier rogue, a bastard sword rogue, etc are perfectly viable alternatives, but not in any way unbalanced and Versatile Duelist is a perfect example of the way feats SHOULD work, new flavorful options but no real overall advantage.