I thought the custom champion voices, at first, was idea gold. If I wasn't so pissed off at the match quality currently, I would buy my favorite champions announcements.
Then I thought it through more... that may detract from the game. Like you're playing your favorite champ and he/she/it is announcing the game as well. It doesn't actually make sense- and I feel like it doesn't make sense from a story standpoint either. I don't know much about lore, or how the field of justice or whatever, works- but I don't think players on the field should be announcers.
I also don't like real life in my video games. We play videos games to escape our world and have fun, like reading a book. Its why non-fiction sucks, I don't want to read about things I could actually do! LAME. I don't want to have real announcers in my games, I don't want that connection breaking up my game immersion.
It seems like... they want us to feel like we're in the lcs or something, or to somehow link our experiences to encourage us subconsciously to watch the lcs---- lol, maybe that is a stretch... but maybe not.
Even if you do like the voices and the jokes- I don't want to hear the same jokes a bazillion times. Just solely from the standpoint of repetition, the new announcers were annoying.
Beyond that, the announcer voice in the game isn't the same thing as a play by play, shoutcaster- whatever. The in-game announcer has one job. To announce game activity in a precise, accurate manner. The game announcer is NOT for entertainment, its for awareness. Its only stating things that have actually happened, nothing else. There is a reason for this, and I think what threw me off the most with the new voices was they were no longer strictly doing that.