We keep getting stuck on the NSFW thing.

Here's my last suggestion on that - after this I shall start considering NSFW a four letter word and try my best to refrain from discussing it.
The board already has an unwritten (now a lot of it written) code for handling that kind of stuff. And to be fair I have only seen one person have a problem with the content in general though there are a few threads that have raised more than one set of eyebrows. Maybe the "report to moderator" step though essential, is too drastic. A lot of people would consider it far easier to hit the back button than click on "Report to moderator" and do whatever comes next...whatever that is. What if we supplement this with a softer approach. People can just choose to flag a post as objectionable, completely anonymously. After x number of objectionable votes that post can be automatically contained within a spoiler tag with a button labeled NSFW, the admins may choose to receive an automatic alert after a certain number of votes.
Two thoughts regarding classification of posts based on subject:
1. We generally tend to have long threads but not THAT many new threads daily, I really don't expect subject-wise tagging to be a problem at all even if the original poster doesn't bother with tagging. There are too many older posts to tag but the useful ones still visited would eventually get tagged and show up.
2. Once we have a subject-wise tagging system in place methinks we should also be able to rate threads, that way if I'm looking up posts on any subject I know which threads are more likely to help.
The keyword for all the above is voluntary. It's quite obvious that most people are happy with the way things are and are wary of change. As far as I can tell none of the above would have any impact on somebody who can't be bothered about it.