A mildly amusing thought.
I've been listening to The Teaching Company's lecture series on The Iliad, and the latest lecture
introduced the concepts of Kleos
(glory, sort of, pronounced clay-os) and Time (honor, sort of, pronounced tee-may). The thing about Kleos and Time is that they have to be visible to be of any value -- to simplify outrageously, they're glory and honor for a shame culture. It isn't enough that you do great deeds, you must be known to have done them and you must be seen to have been rewarded for them.
Now, the Prince Valiant RPG
already had the idea of using Fame instead of experience, along with the concept that it mattered to the fame you got who knew you did your great deeds. Also, you could get fame either for heroic or villainous deeds. But I've never seen it applied to D&D of any variety. (Doesn't mean that someone, somewhere hasn't done it already, of course.)
Now, what happens if you apply the same sort of logic as Kleos and Time/Fame to D&D experience?
Experience for treasure? Sure, getting your share of treasure contributes to your Time. But only if you flaunt it.
Experience for killing monsters? Sure, but the more people who see or hear about you doing it, the more Kleos you earn. Yet another use for hirelings! Also, it makes taking trophies a good idea.
Bards become valuable, too, because they add to your fame/Kleos.
Experience for tricking your way past monsters can work too -- after all, much of Odysseus' Kleos was based on his cleverness after all. But you'd have to tell the story of how you tricked the monsters to get any benefit from it.
I wonder how such a system would modify play? Also, what would be the risks of false boasting and making up victories? Getting caught would probably pretty much permanently crash your fame unless you did something truly spectacular/suicidal to recover it.