When I was a boy, the only thing that was fun about fishing was catching fish. Sitting on an uncle's aluminum boat with a 25 hp outboard, floating on a still, shallow, weedy lake, I wanted to catch as many perch and sunfish and rock bass as I could - using my over-powering 20 lb test line and spin-reel and a bobber and as many live worms as I could squeeze onto the hook. And if/when the fish weren't biting, it was no fun at all - it was boring.
I've hardly fished 3 or 4 times since then - but the times that I have I've gone out with a friend who is a dedicated fly fisherman. Standing by or in a fast moving river, slowly getting better at using only the simplest/essential equipment - a long pole and a very light line and basically a spool as a reel - and developing the rhythmic fluid motion necessary to get a tiny hand-tied 'fly' to drop in exactly the one spot where you think you might've seen a speckled trout.
I've never caught a single fish this way, despite hours out there -- but it has never been boring, and indeed a lot more "fun" than catching perch by the bucketfuls. There is the focus needed, and the learning, and the challenge.
Which is to say: I think worse than the exclusion of fun as a rating criteria is too narrow (and too prescriptive) a definition of fun. It ends up creating an environment where every new course and every renovation of an old one starts following the same template -- ie width, width, width, no trees, width, width, short 4s, width, no water, width, width, width, half-pars, width, run-ups, width, width, no forced carries, width, width, quick pace of play, width, easy walking, width, width, width, short green-tee transitions!