Haven't STOPPED a game, per say, but I've avoided some. Sonic's recent games come to mind--I wish they kept the old voice actors. Their performances weren't anything to write home about--at that stage I think we were all still just happy to HAVE voice acting in a console game--but they sucked just a bit less and had a somewhat better emotional range than the 4Kids actors. I can't blame them too much for any deficiencies at this--it's hard to take ANY dialog from a blue hedgehog seriously, and with Sonic it's difficult to tell where the bad writing ends and the bad voice acting begins.
Final Fantasy XIII I'm outright avoiding after hearing the dialogue in the trailers. Seriously, that stuff made me go from "I'm definitely getting this game no matter what anybody says" to "you couldn't friggin' pay me to play this game." I don't know if it's the terrible writing or the stock anime voice actors that put me off so much. They sound just like everybody else in every other anime-inspired game, and what's worse, their voices don't even match their faces. I don't mean their lips--I noticed they actually bothered re-synching their lips this time--I mean that their voices just don't seem to fit with their character designs. It's not the most jarring disconnect I've ever seen, but their designs are full of flair and personal touch but their voices are totally vapid, wooden, and devoid of personality or soul, like the actors just got bored with their job in the years of basically playing the same people in different series, went in there, read their lines as fast as they could, grabbed their checks, and left. As is often the case, games just inherently draw bad voice acting; everything is rushrushrush on the set of a game and the actors don't get as much room to work, but if anything Final Fantasy ought to be upholding a Miyazaki-esque standard for this sort of thing. You'd THINK that their connections with Disney would get them that far, but it's pretty clear that Square's more interested in pandering to its fans at this point than producing quality work and that their localization crew pretty much just phoned this one in and tried to get it over with fast. Ironic coming from a game with such a huge development time.
