You've identified a potential strategy by which a computer can play like a 1300-rated player, but not one where it will "play like a 1300-rated human". Patzers can still find and make moves in your set of N (if only by blind chance).
Yeah, you would have to weigh the moves based on how "obvious" it is, such as how active the piece has been, how many turns until it leads to winning material, or other such 'bad habits' humans fall for.
