I for one actually like the fun, confident, flirty, and sexy Miss Fortune we currently have in-game.
Even if I don't play her much because I'm not much of an ADC player, It's the MF I personally fell in love with and I know I'm not the only one (She was popular long before even the Bilgwater lore update after all). Now, MF's voice lines right now are definitely lacking, but I like the personality she's got. She's all the things I say in the title, confident, flirty, fun, and even kickass. But now in the lore she's become vindictive for the sake of it just to look more "badass." This game has lots of serious badass characters already, I appreciate current MF's levity. Current in-game MF is a fun character.
To help demonstrate visually what I mean, here's a couple pictures (both official art):
http://universe-meeps.leagueoflegends.com/v1/assets/images/image-gallery/miss_fortune_vs_gp.jpg This is the Miss Fortune we see in the game. Fun and sexy but still kickass.
http://universe-comics.leagueoflegends.com/comics/en_us/missfortune/fortune-smiles/desktop/missfortune-01-21-pa.jpg This is some sort of psychopath. Hollow, fueled by vengeance and self-righteousness but apparently more than willing to abandon her principles when the going gets tough. Seems to have little regard for how her actions affect everyone else. No longer a particularly fun or even likable character.
And just for reference, below are all her in-game voice lines. A lot of people say she's little more than walking cleavage, but I don't see it that way. To be fair, there isn't a whole lot there, but a fun if cocky personality shines through. This is the Miss Fortune I think they should develop if they ever were to do a voice-over update for her. https://image.prntscr.com/image/s7Qly2i9R9aOXDoJ970mbw.png
If they were to change her personality with voice-over, I think they should give her Captain Fortune skin its own set of VO for that. That is, keep her other skins the fun Miss Fortune we have now (just with updated VO), and give her Captain skin its own voice lines to reflect her lore character. It's her lore skin after all. It'd be like a reverse Gangplank deal, where his Captain Gangplank skin has its own less serious VO reflective of a different time for him in his lore.