I really dig Vi's lore but the one question I have is why is it that new champion lore NEVER explains why they are joining the fields of justice?

The new format of the lore, they want to the story of their life before the League to be more appealing then why they joined.

And I understand and agree with that, but I also would like the lore to explain what brought them to the League and why they fight now. They can meld the two together, without bringing about the feeling of leaving anything out.

They said they didn't like one liners, which is ridiculous because those gave insight into all the motives and reasons why they were in the game. You shouldn't have to guess at that stuff.

For instance, Caitlyn is highly tied in to Vi's lore. In Caitlyn's lore, it talks about a bandit who always left a card with a C on it at the scene of a crime and Caitlyn joined the league to hone her skills in preparation for finding this bandit. They easily could have found a way to tie this into Vi's lore to explain why she came to the league.

Who is Vi???

I take it back, I looked her up. I thought Cait says she works alone? It was in the JoJ

My headcanon says Caitlyn kept her close for a bit, then assigned her a different partner and gave Vi only the appropriate jobs. Vi's look and lore suggest a certain degree of recklessness, and while this can be beneficial in certain situations, when it comes to delicate, subtle, or undercover work I don't think Vi would do well at all. Precision is Caitlyn's gig, let Vi handle the less subtle stuff where she gets to punch as many people as possible without getting reprimanded for it.

Plus I feel that Vi should lead a story of her own. If she's attached to Caitlyn as a sidekick(they might be "partners" but Caitlyn is still the Sheriff and Vi's employer), her character loses some of its importance and I really think she could handle more than that. If she ends up with her own partner that is not Caitlyn then she would feel more like the protagonist of her own story instead of a sort of foil to Caitlyn's precision and orderly tendencies. The piont is I don't think Vi needs to be Caitlyn's partner to be important, she can still be a high-ranking officer in Caitlyn's police force and they'll still interact of course, but if we separate the two then Vi will have that much more room to be the protagonist without constantly having to compete with Caitlyn for our attention.

This is nice and all but no where near the original question of this thread. I just want to ask why it is that Riot does not include why these new champs are fighting in the fields of Justice. Some of them make absolutely no sense without some kind of back story of introduction in the league.

kitae had this to say about the "Why join the League" question in her AMAs Returning thread:
Problem is they aren't delivering and we are forced to improvise as a result. Also I don't agree with the one liner not giving new info on the champion. It gives info on why they joined which from all the questions means that it's "new" and unknown information.