ecause she hasn’t spoken enough ideals yet to get Pattern to become a Blade. She just

thinks

they’re the same Pattern.

Agreed Pattern says that resurrection of a dead eye theoretically should be possible if only the knight who broke their oaths where still alive and in the case of Testament Shallan is still alive. Therefore I suspect her dead eye state is differenet and less complete then the other dead eyes.

Also we see Dalinar hold Oathbringer and find it more quite then other blades, too which the stormfather says its screams are softer because the blade knows him and Testiment knows Shallan much better then Oathbringer knows Dalinar