There's a point where "best job they can" becomes just a plain old bad job.
Oh, certainly. Not every translation is going to be good. Then again, I consider most fansubs I've been exposed to as lacking in their translations because of all the things we've been discussing.
I can confidently tell you you're wrong. How? Because I, and many others, watch fansubs that leave the honorifics untranslated and it seems perfectly natural. After watching a couple of shows you don't even notice; in the same way that you get used to reading subtitles themselves; or the gigantic eyes; or picking out seperate lines of counterpoint in some intricate baroque piece, though that probably takes a bit longer to learn. People adapt. What I, and surely most people, can't adapt to, however, is the unidiomatic use of my native language; it will always draw attention to itself. Also, of course, English is full of foreign words and expressions. Learning a couple of new ones isn't a problem.
Well, I can confidently say you're wrong from my perspective. I've been watching anime for years through fansubs and it still feels utterly unnatural to me and several of my friends who watch anime, though not as regularly as myself. Reading English and suddenly seeing Japanese interspersed is so completely distracting that I can barely comprehend how someone can think otherwise.
I think part of the reason for the "adaptation" is there aren't as many options when it comes to fansubs. Most groups do these sorts of shotty, cliquey translations and it's less peope adapting to it and more having to accept it due to no other option unless the show is officially subbed/dubbed later.
"This is my big sister, Anne" is a bit different to "Big Sister, I'm going to the shops now. What should I get, Big Sister?"
Like I said, dialogue itself is not 100% natural.
In your example, after introducing the characters you shouldn't need to remind the audience constantly of the characters relationship anyway, it's redundant at that point. That Japanese quirk can be dropped in most conversations between them without harming characterization.
I was going to write a more detailed reply, but really what's the point? We're just going to go in circles, thoroughly entrenched in our respective camps.
Welcome to the internet.
It's "Sir" with a capital "S". The problem with it is that Naratu is about ninjas, but the Crunchyroll translators are using words that evoke, at best, the English aristocracy, and at worst, King Arthur and the Friggin Knights of the Round Table. It's very, very distracting when some character who's just a ninja is referred to as "Sir Gawainu". Sure he's a true ninja among ninjas; he's respected as a wise and powerful ninja. BUT HE'S A NINJA, NOT A KNIGHT.
Meh. Perhaps there could have been a better translation in that specific case? I don't know, I've never bothered watching the show and I don't watch shows on Crunchyroll so I don't know if their standard of translations are not quite up to par.
Off the top of my head, I could offer maybe a better translation would have been "Master" or something? Would that not be suitable?
When you put it into context I can still determine the distinction they're making though, so it does come off as understandable much more than leaving foreign words in the sentences.