The idea of lowering the effective range was to have different niche's for the two weapons - the crossbow does more damage, but requires you to put yourself at greater risk by needing to get closer to hit targets more effectively.
I thought the biggest difference between bow and crossbow was in fact the action points needed for one shot with the crossbow. While using a crossbow my ranger could usually just shoot one arrow each turn while he was able to shoot two or even three shots per turn with a bow. Of course one crossbow shot makes a lot more damage than one bow shot which makes them pretty even.
