I was digging through some very old paperwork last night and ran across this, back from whence I (unsuccessfully) tried to sell a script to ST:TNG. Unlike some others, I didn't go the "open door policy" method but rather got an agent (in fact, mine was Ron D. Moore's first agent) who had contacts with the show. This is why I was able to submit some written pitches instead of spec scripts (though I did those as well). I thought some of you might be interested in the kind of feedback one gets from actual writing departments.
One thing you'll notice is that the memo very carefully sidesteps suggesting that the author do anything because the WGA would look upon that as an "assignment". Instead the memo points out things that could potentially be issues with the stories pitched.
I'd forgotten what a lot of these pitches were until I dug them out of my files, and in retrospect it's obvious that most were too plot-centric and not about the characters propelling the story. Also, I should have genericized the aliens instead of doing callbacks to earlier shows, since that made the stories seem more "gimmick"y than they actually were.