You assume correctly that the easiest way to require skill for certain weapons is to require skill in aiming, and leading the target, and timing your shot. This may have the disadvantage that you will draw in some of the FPS crowd. It is usually -and I’ll remain polite- a much more vocal, and much harder to please crowd.
But there are other ways. One other way to require skill from the actual player, is to replace the entire “fight” with an appropriate analogy. If I may return to the Magic: the Gathering analogy: players also shoot fireballs, wield swords, and send lesser creatures into the battle. Only they do it in playing the necessary cards. The skill lies not in aiming the weapon. Rather, the skill is in knowing when playing this weapon will do the most damage possible. Of course, your RPG will suddenly become more turn-based, and possibly less interactive.
Perhaps there are other analogies for a swordfight and a gunfight, that will attract the RPG playing crowd, and still require ACTUAL skill, rather than artificial skill numbers. For example: in Monkey Island, a duel between pirates consisted of the two duelists shouting insults at each other 8)