I'm a Horse Archer, which according to this thread should doubly penalize my points. If it does, I must be truly awesome!
On maps that aren't city streets, I often rank near the top of my team in points and have gotten valour quite a number of times. Perhaps that is due to playstyle?
I don't circle off at the edges of the map trying to plink from afar. I'm either chasing other horses with my mounted teammates, or I'm circling close to my team to kill off the enemy cavalry that tries to break their lines. If no enemy cavalry is around, I'm near my teammates to put some stun arrows into the enemy so they can get a kill, or taking the opportunity bump to knock them down so the teammates can get a kill.
Foot archers can't extricate themselves from a bad situation as easily, but they don't have to spend a ton of points into riding and HA either, so it should balance out overall. Stick close to your infantry, pull out your own sword in sticky situations so you can block attacks, then pull out your bow again when you and the infantry have eliminated the immediate threat.
I think ranged scoring is just fine. Playstyles to maximize your scoring effectiveness is probably what needs to be tweaked if you care about your score.