Fact is, my position is really simple. If Bioware decides they can add a filter without hurting the meat of their game, the story, the characters and the gameplay, and choose to do so, let them and there will be no need to complain as it is optional. If Bioware chooses NOT to include the filter due to resources or any other reason, then by all means. It just means that the people buying the game will simply have to accept what is there and deal with it, or skip over content when available because warning labels exist for a reason.
That's the long and short of my position.
Gore filter: Tricky. You can hide persistent gore cause that's just a texture but that's as far as it goes. Exploding heads and other gruesome animations are much more difficult to hide or replace. Same is true for bodies on the ground and other parts of the map that could be classified as violent (heads on pikes etc). I don't really see a way to implement a toggle for those without actively cutting out content, which in turn would change the impression the game is trying to make. Hiding body horror stuff like the Husks, Cannibals etc is impossible.
Nudity filter: Difficult to do without turning serious scenes silly. Unless the writers compromise and remove dialogue from sex scenes, you can't skip them without missing out on content. A toggle would mean that you don't show T&A, which could be accomplished with different camera angles or just showing the faces ... that would "only" require to create each scene twice. As an animator I wouldn't be confident if I could get the same tone in both scenes though. Another option would be an overlay that blurs the offending body part or covers them with censor bars. This is akin to the bleep problematic and would look kinda silly and/or break immersion in a big way.
Language filter: This one is hard. Option 1: Record different lines. This is obviously a bad idea because it would be costly, inflate the size of the game and make it next to impossible to write good, consistent characters. (Example: Vincent and Jules from Pulp Viction are completely different people if you replace all the swearwords.) It would mean the writers would have to create characters that work the same in both versions. Personally, I can't imagine how that would work without changing the mature version first so it can be used with a toggle. At this point it would be easier to just make the censored version.
Option 2: Bleep out the offending words. You have to find the words in the game and either play a second track on top of them or stop the playback, play the bleep, jump ahead in the file and continue the playback. Then you do the same to the subtitles.
You'd have to do that for every single language seperately.
There are multiple, serious problems with these filters.
First, you need a way to determine what needs to be filtered out and what is okay. As pointed out before, there are many different rating systems worldwide, all with slightly different standards. If you don't want to use those, then you have to come up with something by yourself. What is okay? What is too much?
Secondly, it isn't profitable. The game would still be rated M, so it's not like you can reach a younger demographic with your toggle. How are you going to pay for all the additional work? People would need to do research, they would need to do a fair amount of coding, they might have to create new cutscenes, record new VOs and then test all of it. From a business point of view, such an investment with basically no return makes no sense.
Thirdly, adding such a feature makes the game more complex. I'm not saying it makes finding bugs exponentially more difficult but it introduces new factors which will have to be accounted for. So instead of testing 4 possible bugs, you'd need to test 8. It also increases the size of the game, which could mean additional discs for shipping.
Fourthly, do you apply the same filters for each market or do you create different ones? For example, a nudity filter wouldn't see much use in Germany while a violence filter wouldn't be used much in the US.
Fifthly, if such filters were possible, then why haven't they been used in games before? If there is profit to be made, if there is a demand, if it is possible... why doesn't it exist yet?
Sixthly, you will still run into people who aren't satisfied with the censorship, because they have different standards. You can't ever create a filter that's good enough. Example, we have a language filter in this forum and we still have an user going around and reporting people for their use of profanity. Coincidently it's someone who's very vocal in his demand for a Toggle.
Personal comments: I have zero problems with nudity and I'm still amazed at how uptight some people are. Oh noes, a nipple! Well, so what? They are just breasts. Mighty fine but not the holy grail or something to get overly excited over. Nudity doesn't need to be sexualized.
Showing violence in games is okay when it's necessary for the gameplay/story... but not if it's gratuitous.
Strong language needs to fit, too. I think so far BioWare has been very tame with the language and it didn't reflect its use in RL.
Having options is good, yes. But buying a mature game and then wanting to turn off the mature parts doesn't really make sense. It's like ordering a Vindaloo curry and asking the chef to not make it spicy. Why not order a mild curry in the first place then? It's bound to be better.
Conclusion: Those filters (the famed 'Toggle') would require compromises from the writers in some form (try to write dialogue when half the words are bleeped out and still deliver the same tone and context), it would require a lot of money, time and other resources to implement and there is zero reason to believe it would actually recoup any investment. Additionally it would make testing more difficult, which translates in longer times for bugfixes and patches.
I can't see any way how such a filter (except for the persistent gore one) could be truly optional without affecting the players even if they don't use the toggle.