Asides the fact that you have seemingly abandoned the thread when it has been moved towards a section where you will receive a bit more relevancy, I'll do so some nitpicking of my own.
Your suggestion was to hire two or more people who have experience with medieval and other settings like that. You fail to account for, according to Babag, that this is a society which has advanced through magic so those kind of things are not purely relevant. You would need someone with a history in fantasy with the ability to properly join together the notion of magic and a more present situation.
Your argument about Thresh and whatnot, well I found that really, really silly. The context that this is a game comes first, direct lore interactions can be waived away largely because there are summoners controlling them leading to different results then would normally occur. This is why when Morde or Karthus steal a soul, it is not gone forever. It is why Thresh can collect souls on the field of justice because it furthers game design. This is fine and dandy under the circumstances that the writers are creating a consistent and logical world, which I agree they aren't.
Your objections against Vi, while nitpicky do make sense. She is an entity who's only real skill is punching things with hextech gauntlets. Nothing about her personality really conveys a reason for her to be unique outside of them so I will give you that one.
Overall, I believe the majority of your points are so fine and diminutive that they are near worthless in comparison to the big issues at hand. Overall, you make a problem out of things that could be explained away in less then a paragraph such as "The effects on the league do not have a permanence outside of mental to the characters and after they 'die'." It's a cheap way to do it, yet it removes quite a few of your qualms.
To me, the bigger problems are indeed the lack of consistency. The fact that the lead writer has coined the term "Factpocalypse" and other things that show a desire to create one off stories that lack consistency when put together. The lack of communication between the players and the lore writers, because if there was more communication outside of heavily limited AMA(A)s then the players would at least feel better about discussing and playing in the world.