Voice acting can sometimes be a bother to create, particularly for games that are designed around you designing your character. Mainly because you might create a character who you'd think would have the voice of James Bond only to find that the only male voice for the Main Character is Phil LaMarr (don't get me wrong, the guys a fantastic actor, but he's been typecast as the stereo-typical black guy one to many times).
This usually only occurs within a certain scope of character creation. By that I mean that if you can choose the race, gender, and general look of the character, you probably shouldn't voice it as (and I know this sounds bad) people expect certain races to talk in different ways. Gender and physical build you can get around, Gender by simply rerecording all the dialogue with a different actor (and in Mass Effects case, Women Shepards got the better voice acting... but that didn't beat Keith David). Physical build is easy to get around because people don't sound very different based upon their build, mainly the height is the problem (and you generally can't make a character so small/tall that it'd have a huge impact on how they sound.)
RPG's also have another problem that they've been finding interesting workarounds for in the dialogue. And by this I mean the fact that in RPG's it's EXPECTED to give you a choice of name. Now I've seen three major ways around this, your character is given a moniker to go by, your character is given a last name that cannot be changed, or (and this is the harder one) your character is only referred to by nouns. That last one must be MURDER on the dialogue guys, but when done right it comes off fantastically well (see FFX).
FPS genre on the other hand I think need to get themselves out of the rut that the player cannot talk. I'm referring primairly to the fact that protagonist in FPS's, while having names (Gordon Freeman, Pvt. Jackson, Soap McTaverish... Pretty much every protagonist in COD has had a name, same with Medal of Honor) apparently don't know a lick of english. And the writers usually use another character (Gaz, Alyx, Griggs etc etc) to relay important information. And while this is good to a degree, sometimes it can come off terribly (particularly in Half Life, where Alyx has FANTASTIC conversations... with herself).
While I understand this on one level, they don't want to project a personality that the player feels they have to conform to, I think that this idea is overall stupid. The player characters are given personalities by the interactions other people try to have with them. Ok, Gordon Freeman is one of the few exceptions to the rule, as his only personality seems to come from "I am a walking armory with a Doctorate degree in theoretical physics... RAWR" and yet it's still hinted that he and Alyx will be bumping uglies in the epilogue of the half life saga... if not sooner. But come ON, you've given these people Names and definitive looks for the most part, but you don't want to give them personalities because you might loose customers? How about this, you hold an open audition for any male voice actor to come in and try to do Gordon Freeman in a single paragraph of lines you make. Then you put all that audio on a sight and ask fans to decide who sounds the most Gordon like. You'll probably end up with one major winner and a runner up who has most of the rest of the votes not for the first guy.
I guess if you're going to have characters try to interact with a character who's mouth is sewn shut, DON'T. Otherwise Voice Acting should be done well, and try not to make every character sound American unless you have a plausible reason (Altair's actions were seen through the eyes of an American person who'd put American inflection into how they talk in memory. Altair might not actually sound American to everyone else, but to his descendant he'd have no accent.)
