I can understand where the OP is coming from. Sometimes the gore is overboard, and sometimes the language can seem a bit too much.
However, yes, adding a toggle WOULD cost more resources and more time to do, due to the coding, and the time taken to find those lines and bleep them out or replace them with something less offensive. And then there's the whole "editing out the sex scenes" bit, even though those rarely show much in the first place.
What I would fully support is a "disable gore" option. I don't care about the nudity since there's probably just going to be one scene per playthrough that includes it. I mean, there's other risque stuff too, in Mass Effect. If we're going to make optional censors for nudity and language, how then will we handle things like Chora's den? The asari dancers? Do we find a way to censor the drug use, smoking, prostitution as well?
Some scenes, and some dialogue, are part of who a character is or part of what a setting is. If you're going to an exotic dance club, you're going to see nearly-naked dancers (why can't some of them be men?). If you're on Omega, people are probably smoking, doing drugs, and having sex.
I don't want to disrespect the OP, because I get it. Some of this stuff takes me out of my comfort zone. I'm frankly less okay with the gore than I am with the sex and curse words. Hearing language in this game won't do much to me, because I hear it in real life too (every time I boot up multiplayer, basically).
I don't think it's somehow "weak" to think that foul language, nudity, gore, etc. are going to morally corrupt you. It's a valid concern and let no one tell you otherwise. However, the effort to make toggles to hide all of this would likely take resources away from some other part of the game.
And let's be honest, Mass Effect has, thus far, even at its worst, been remarkably mild for an M-rated game on language and nudity and yes, even drugs. Omega in the books seemed much worse than in the games, in terms of drugs and sex and violence. It has its moments, but then, for characters like Zaeed or Jack, their language depicts who they are. I might not like it, but I wouldn't censor it--I've heard people who use far worse language.
I don't want to sound rude, but again, aside from a gore toggle, I can't support the "toggle all of the offensive things" idea, when it sounds like what you want is a really good, plot-heavy Teen rated game. With a Teen rated game, you wouldn't need these toggles. And yes, I know, it's not the same--it wouldn't be Mass Effect with the characters and setting you've come to know and love.
A gore toggle would be a great idea. I usually had the gore turned off in DA:O and DA2. I wanted the option in ME3, but it wasn't available. It isn't that I can't handle the gore, but it's kind of gross and, well, in Dragon Age it looked more than a little weird when you were flirting with an LI while covered in the blood of your enemies. So there's that.
OP, you may end up having to make a difficult decision to either give up Mass Effect (assuming ME:A is not much milder than previous titles), or to simply accept it as it is.
BioWare does listen, so it's possible they might at least consider adding language/nudity censor toggles, but I repeat that adding such toggles takes more resources than you seem to be aware.
Again, you have to go through and review all of the voice acting clips, and all of the video clips, and edit them *just so*, and then things sound awkward--or, you might just have to re-record every line with different words in place of the foul language. The nudity would require editing every romantic scene clip that contained it. That's not even mentioning how having dual versions of certain videos and sound files would bloat the size of the game itself.
If you want my honest opinion, I'd rather they did not expend resources adding censor toggles to their game(s), other than, again, the gore toggle (and in my case that was mostly an aesthetic thing). The more resources they put into things like that, the less they can put into other areas of code, voice acting, voice editing, and video editing.