Just differing points of view, Sainna, nothing shameful in it. I was exactly the same way until about a year ago. Infact, I still am in many of my hobbies. Its just Warhammer has always had a very maliable canon, to the point it actually barely had one when it first released from what I understand.
Also just keeping up with the changes are difficult; like I mentioned, the Tomb King army book pretty much renders the Nagash Trilogy none-canon, by changng large parts of it, which could very well extend to Neferata, as it is basically a continuation of her story based on those books. So arguably its already happened. It basically comes now to the ToL Nagash books changed a lot of pre-established lore, not just from the Necris but from the army books from what I can gather, and the lastest Tomb Kings book has stuck wth its guns.
People don't keep the wiki's up to date, and to know it all you would need to own all the supliments and buy all the army books as they came out, and few have that sort of cash. The Tomb Kings army book goes into Arkhan and his backstory, telling a different tale to the ToL books. Neferata was the one who wanted to trap and kill Khalida, and then tred to turn her, before the goddess stepped in due to her faith - which couldn't happen due to the ToL severing the Nehekharans connections to their gods. Instead it had it as Khalida was just too far gone to drink. Hell, the latest tidbit I got was Arkhan assaulting Altdorf and seizing the Liber Mortis, and thats from the Empire book. I just happened to have friends with both. Who knows whats hidden in the timelines of other army books.
So while I respect your desire to follow the stories the authors want to tell, for me personally its too much hassle, if not impossible. Any author can write anythng he wants practically, stomping on others writers creations in the process, as the author of Nagash (practically) admits to doing in his foreword. They don't have a lore master like the TES series or Star Wars to make sure verything is as aligned as possible, and to correct authors upon recieving drafts. This leads to differing tales almost every time, and changes wth each release. Factoring in the issue that army books come first, and the writer don't seem to give a damn about the Black Library, things can reset or change in something as simple and tiny as a throw away sentence in timeline. Then we also have to factor in that some books can be put under the Unreliable Narrator tag like the Gotrek and Felix books, or Genevieve which if remember right is widely regarded as a fictional play in the Old World, and you have a real mess that in my mind is almost impossible to actually keep straight.
Mike Lee wrote in his forword for the Nagash trilogy: "..."Send me over the background material and i'll start working on an outline"... What I recived, a month or so later, were about twenty photocopied pages from the Tomb Kings army book. They included a couple of maps oh Nehekhara, a chronology listing the major events of Nagash's reign of terror and a brief history covering the origins of the undead. That left me a great deal of creative freedom to portray the land of Nehekhara and its people, as wel as characters who find themselves caught up in Nagash's evil schemes."
Basically he recieved a fraction of the actual background materials already a part of the world, even if you want to discount the Necris and Night's Dark Masters both, and bascally went on to write whatever struck his fancy, even if it conflicted with previous (or future for that matter) lore. I don't think he actively chose to throw out Abhorash, he just wasn't menton in the timeline or materials he worked off of. I may not be a sucessful author, but it seems common sense to at least read up a little on other sources, rather than relying on what little he was handed in a rich world like Warhammer. Its like being handed a couple of chapters of Lord of the Rings, and going on to re-write the Hobbit from details Bilbo mentions. He didn't do his research.
So, yeah. I'm not going to say you are wrong to respect an authors right to tell his story his way. I just personally find it hard to respect dozens of authors stories told their way when they conflict, and worse, trample previous lore, and ahve over-authors who write the army books and in turn trample their stories. Its like the stampede scene from Lion King it litrary form.
--Edit--
Also, I found those quotes you asked about in another thread, about there the idea that you can pick and choose comes from amongst fans.
"With Warhammer and Warhammer 40,000, the notion of canon is a fallacy. [...] Warhammer and Warhammer 40,000 exist as tens of thousands of overlapping realities in the imaginations of games developers, writers, readers and gamers. None of those interpretations is wrong."
-- Gav Thorpe
"It all stems from the assumption that there's a binding contract between author and reader to adhere to some nonexistent subjective construct or 'true' representation of the setting. There is no such contract, and no such objective truth."
-- Andy Hoare
"There is no canon. There's a variety of sources, many of which conflict, but every single one is a lens through which we can see the 40K setting."
-- Aaron Dembski-Bowden
Those... actually allow me to view the authors more favorable, and their whacky stories. I don't think much of it as a storytelling stance, but if thats what they have gone by, whatever. It also render my entire post rather pointless really. Ah well. As someone of DakkaDakka put it "We can't keep track of our background material well enough to have an established canon, so feth it, there isn't any."
Kind of takes the wind out of ones sails.