Youre too trusting. Until larian says it missing is a bug/its just not implemented yet because its not finished i am assuming they simply forgot about it and we will never see it unless we nag them constantly.
They are trying to design the whole game. In addition to them handling the specific game and story they are making, they have to handle their mechanical implementation of the things that are not covered by the system but need to exist in a computer game adaptation of it. This gives them three distinct things. The base rules as a block, their non mechanical game design and story, the required adaptations to implement it all together. This means they do not have their minds focused so intently on comparing specific subsections of the rules to their game like a player trying to use understanding of the system to better understand this game might. This amount of specific focus is simply not going to be there.
Whats needed perhaps are full time class advocates and rules lawyers to constantly be pointing out conflicts to them and trying to bring out the richness of class flavor. Even if its not so important mechanically in the game as it currently is, the nice feeling about conceptually being super-skilled at certain things is enough to make the difference between picking one class over another. The sensation of 'being a rogue' can be made or broken by the knowledge of those skill checks being strongly in your favor. Many of the current complaints and concerns of the game do not need immediate fixes in the game itself and could be solved by simply having developer aknowledgement and the reassurance that it will be fixed at some point.
The mechanics create the fantasy. When your class has a certain mechanic, this grabs the imagination and immerses you in the class. Things like the current abjurers bonus hitpoints counting differently than it does in pnp actually affects your immersion because it changes the way you conceptualize what this ability is doing. The mechanics effectively are the character, and so for a rogue to be skilled, the mechanics must say they are or it wont feel right, you will not be immersing, but pretending on top of an immersion, your rogue will not be skilled but will only think it is.