The problem seems to be one that is on multiple levels. The first, and easiest to address is how hostile we are being directly to Riot and Rioters. A lot of people value the characters and their lore, so when they see their lore being taken apart and brutalized (Soraka's new lore, Jayce's old lore for example) they are going to be a bit feisty, combine this with the lack of quality in new champions people are not happy. What the community needs to do is take this frustration and turn it into better written arguments for their opinions. Of course, there is always a point when we must say that Riot isn't listening but you have to do it in a good way. I'll admit that my own writing style can be abrasive, that is a personal flaw but I highly doubt that most of the lore community doesn't know how to write arguments that are a bit friendlier.
The next part of the problem is that even when we behave, Riot doesn't seem to be listening. There was a lot of outrage at Jayce's lore because it made Viktor so archetypal and just ruined his lore. This trend has continued, while some things are not outright contradictions when you look further on the personalities of the characters are getting changed, which means the entire character is getting changed. (Karthus's new lore/personality for example) Riot continues to follow down a path that the lore community at least has shown a lot of dislike of, they are also forcing older characters down this path.
Third, the uniqueness of the characters in the world is forcing a lack of originality. This statement on the surface doesn't seem to make much sense but when you look at it, you'll see things like Singed and Warwick's lore, they were not unique because they both filled the roles of chemists but the interactions between them and Soraka, at least in my opinion was original, it was interesting and furthered the world and characters.
Fourth, because of all of this the tensions between the community and Rioters is going to grow worse as time goes on because communications between both sides are fairly limited. From the community, it's the aggression from being well, spoiled. From Rioters, it's the selective answers they give in addition to what just seems like not trying to work with the community. When Babaganoosh worked on the lore, it didn't require an AMA to get a question answered. Things that weren't directly related to the champions were fleshed out, a reasonable, REAL world was provided.
I've put forth problems, so I'll try to put forth solutions.
For the first problem, we need to calm down. Arguments need to point out the difference between old lore and new lore, what made those good and where they could have been improved. Stomping our feet and saying "We don't like this!" isn't going to fix anything. Saying that Soraka's old lore was problematic because it made her seem air headed, so expanding on why she stooped down so low would be better.
As for Riot not listening. They should try to become more visible, threads that ask questions, REAL questions should be answered. It may be just me, but I don't care about a hypothetical situation between two champions that isn't likely to occur. I want to know what has happened, I want to know what is happening, the characters should feel like real people rather then larger then life stereotypes. Questions that aren't related to champions, or even to the league should be ENCOURAGED. We should at least have a way to find out more about the world.
Characters shouldn't have to each fill a niche little role within the world. I understand gameplay-wise that having a champion's looks, and abilities stand out and fill their own roles is needed. For the lore aspect, this isn't as necessary. It expands the characters, we have 100+ champions with a lot more in sight. This means that letting characters and what they do overlap isn't that bad, using them to flesh out the world is kind of useful but of recent even that hasn't been done. One outlet does not make a proper world, the more ways you have of showing how the world works the better but simply trying to say how it works using one method doesn't work.
As for the final point, well if you fix the first three then the last one shouldn't be a problem. It might, but that is beyond the scope of my own vision.