One of the gameplay guys might be able to answer this better, but the general philosophy has been to not limit creativity when creating courses. Instead we've tried to formulate our statistics in such a way that there's no advantage to playing an easy course. You'll see low par score for your round, but so will everyone else, so you won't shoot up the global leaderboards.
I wouldn't play par-3 courses all the time, but it would still be cool to see some quality ones being built.