Whether the readers and writers are looking for mindless action or intellectual challenge is up in the air as I see it. For the readers, I couldn't tell you with much certainty, though I doubt it is at either extreme, and it likely leans more towards the former than the latter. For the writers, I've found it varies, as people like
Semievil would go into the negative on the mindless extreme (a trend I'm sure appears often in those burdened with a lot of work and stress on the mind) and people like
The Last True Evil (correct me if I'm wrong) find it more difficult to craft anything
other than something intellectually challenging. It's funny, because the two of them certainly have a strong potential to craft on the opposite ends, and I just think it goes to show that the NeS is the place to do the impossible and be on both ends at the same time. All things considered, though, intellectual challenge in the NeS should not come at the cost of mindless action, and I think both readers and writers would at least agree to that much.
Want to get your head into this and your hands dirty? Then please question, comment, criticize, and analyze with this lens yourself!