Yeah, it's definitely awkward when the author doesn't realize there might be a problem here. A fantasy/fetish scenario (unless it's really badly written) is still a treatment of the issues. It's like the difference between "mmm, that's some good non-con" and "what do you mean this isn't a sweet romantic love story?"

On a completely different note, thinking about Jenny/Vastra (the only lady/maid pairing I've read recently), most of the fic I've seen hasn't gone either way. Vastra doesn't seem tuned in with that part of human dynamics, while Jenny knows her skills are irreplaceable and her value far in excess of her paycheck. So they're written as plausible power equals for in-character reasons.