Story-writing is not good if the reader is confused about what they are reading...
Example...I started asking questions about The Avengers to some of my comic book reading friends, and they kept asking me "Which Avengers?". I'm like...um...the only ones? Come to find out, there are multiple Avengers "universes" in which the same characters show up in different versions of similar settings...it's all very confusing. Eventually, I decided to just follow along with the plot of the movies over the last few years, and it turned out that worked just fine, since they are all very cohesive (even if the actors used are not 100% consistent).
As Larcent has pointed out, I think that we, as Players, could stomach ONE change per champion/setting/storyline/event and then that is the final say. Once something has been "updated", that needs to be the final update.
I like to think of The Forgotten Realms as a great example of this...Overall, the basic world structure, major events, etc. are all handled by the company that manages the Forgotten Realms lore. But the individual stories (such as the Legend of Drizzt) has largely remained consistent, yet fills in gaps in the story of the world. Sure, there will be times where something needs to be changed to remain consistent, but the change per item should only be ONE, and afterward, it should remain that way.
This means that people just getting into the lore can actually find proper information on the background of, say, WW and Raka...and won't be confused too much by finding out-dated lore if it's only one other version. I think where you run into problems is the possibility of finding more than one old version of any given story, OR the fear of a story you already know getting some crazy change to it in the future.