A Simple Request from Thieves: An upgrade to Thief's Knife.

[Arcon]

That would not solve the problem of THF's knife being forced in our hands, It would just be a matter of Mainhand the new one and offhand THFs Knife.

The main issue is the whole "another dagger with TH = you still have to use Thief's Knife" thing.

Same issue with Synergy/ToM. You could still have the base weapon and the upgraded weapon. You can do it now too, why would it be different for the Thief's Knife?

For all I care, they can remove the current Thief's Knife from the game as well. Although honestly, I don't have quite that much of a problem with it, it's an acceptable trade off imo.

[Economizer]

why would it be different for the Thief's Knife?

The name of the item does not change, only the level will. Meaning that you can't have two of the Thief's Knife even if you augment one. With ToM there aren't a lot of examples of same named items with different augments, but they do exist, and you can't have more then one of them at a time.

Basically, augmenting the knife itself and not changing the name would mean that the rare tag is preserved, and more importantly, you don't end up having to dual two of these things just to max out possible TH gear.

Either Trials of the Magians or Synergy will accomplish this in a reasonable manner.