You can go one further, if you want to de-emphasize the combat focus in D&D, which I've very successfully used and seen used by others. Rather than awarding XP for killing things, simply award a certain amount of XP every session, irrespective of what the PCs do.
Which is something that Vampire, GURPS, Mutants & Masterminds, etc. pretty much already do. Your 'points' at the end of the session aren't determined by how many mobs lay dead before you, but by your completion of mission objectives or by your roleplaying. (Although awarding a certain amount of XP regardless of what the PCs do is, IMO, a step too far. Even if the objective isn't conflict-based, the PCs who contribute to advancing the storyline should get more XP than those who do nothing or actively mess things up...)
2E seemed to be moving in this direction, with a plethora of ways in which one could gain XP by using class abilities, but even then, they were typically awarded for 'in-combat' or mission critical uses of class abilities, so that the party Cleric couldn't level up by casting Cure Light Wounds on the townsfolk between adventures.
I've swapped out characters in games of Vampire where any attempt at building anything was foiled by random Sabbat invasions / Werewolf attacks / cranky Elders showing up and taking everything and just swapped to a Brujah with 5 dots in Potence, since doing anything constructive was actively discouraged. Sometimes punching crap until it dies is fun, too, but it's terribly frustrating to be playing the Bard with social ties out the wazoo or a Cleric who wants to found his own temple or a Wizard who wants to do spell research / scribe some scrolls between adventurers or a Halfling Paladin with a big family or an Artificer when the DM is planning on running World's Largest Meatgrinder.
It's kinda vital for DMs and players to work together on the whole pre-game communication thing.
