This is a GREAT topic. Being new geocaching (and therefore the logging process), I am not as familiar with the experience or expectations of logging. Luckily, I am actually a writer (not as a profession, but it is just something that comes naturally to me) - so just like in real life, I tend to be verbose. I think it is fun to share with the cache owner and others who may read the logs a little of what my experience was like hunting for their cache. I of course, like to add humor, because I enjoy witty remarks others make too.
However, now that I am a cache owner (as of just this week), I ESPECIALLY appreciate the "lost art of logging". I agree, as a placer of a cache, you go through some heavy homework and effort to get one placed and approved and you wanna hear something more than TNLN or some acronym variation of the sort. In all fairness to cachers though... if a cache is not in an interesting location or it is really easy or obvious, there is probably not much to say. But the ideas provided in this original post are great considerations to pull some sort of comment out and add a little description to the log.
Now, in a related subject, you know what bothered me with my first placed cache? I left some "swag" for the FTF cacher (I believe swag refers to goodies you leave behind that a cacher can take and keep - correct me if I am wrong please)... and the FTF cacher never acknowledged it in their log. I mean it wasn't super valuable but it did have some symbolism and meaning and the least they could have done was say THANKS... too much to ask?!
Oh well, I don't want to end this on a negative note, so I hope lots of people read this thread and realize the value in writing a good log. And by the way, good doesn't have to mean long (kinda like this reply, ).