Well to be fair when Lucas allowed publishing to go forward in 1991 not only did he not have any intention of making the prequels at the time nothing was even written not even rough form til nov 1 1994 for episode 1.

And if Lucas had no clue of how the story would happen, there is no way even if they wanted to that they could clue Zahn into something that was entirely static and changing up til May of 2005.

Obvious things Zahn wanted were nixed the Noghgri being the Sith race. Obi Wan's insane clone. Heck he even used Dark Jedi confused as to what Sith meant.

Darth Vader had always been known as a Sith l but for some reason when they did the publishing line in the 90's everyone was a dark jedi all of a sudden. Even the emperor, dark luke skywalker etc. Either the term was off limits or they were confused over its application.

To me one of the dumbest things Lucas came up with was that all Sith had to have Darth in their name. Palpatine suddenly had another name Darth Sidious. He could have been a sith Master or acolyte of the darkside without Darth in his name.