I wanted to throw out a DMing biscuit by way of example:
rival NPCs.
My players were at a relatively low level (2 or 3), but starting to feel like Hot Stuff when I brought in an outside party of NPCs to "take control of matters". This group was locally famous and referred to themselves as the "Fabulous Five". They came to this podunk locale after word got out about some of the hauls the PC were bringing back with them from the dungeon. They proceed to take charge of the situation and treated the PC in much the same manner as PCs treat hirelings, e.g. meat-shields, horse-watchers, no role in decision making, flat-fee (vs. share of the treasure), tried to intimate them whenever the PCs complained, and generally claimed all the credit while minimizing their own risk.
The PCs (who originally sucked up to them because they were famous and powerful) quickly learned to seriously DESPISE those jerks. Even now, years later, if anyone mentions a rumor of the "Fab Five", the party goes ballistic.
I present this an example of the world creating its own motivation (revenge on those bastards!), that is engaging and is unrelated to treasure or XP. I think its something we need to be mindful of as DMs. It's our responsibility to suck the players in to something beyond a formulaic routine of Fight-Treasure-XP/Level-Up---especially at higher levels when it breaks world-balance. We want to instead get under the player's skin and keep the brass-ring dandling just barely out of reach. It's not
having a thing that is fun, it's
chasing it. D&D should never become a game of driving around in a limo with a hot-tub in back and a girl on each arm like some 90's rap video. If and when that starts to happen, it's truly game-over.
For sake of quotable hyperbole I will stick my neck out further and make the following (hopefully controversial) blanket statement:
A good experience point system is one that motivates players to take major risks and begin exploring the world, by rewarding active play sufficient to achieve 5th-level (zero-to-hero/magic-user-gets-fireball) over the course of many months of adventuring. Beyond that point, it is irrelevant that the same mechanism that worked in the early game is by-and-large useless and/or broken, because the momentum of world-play will carry the action forward, and should (rightly) shift the focus away from character-level advancement and acquisition of XP as the primary motivator towards other (self-selected) goals.
In his review, Byrce frequently chides an adventure for being too low on treasure in a GP=XP system. What I'll suggest is that he should instead focus on "
Does this adventure provide sufficient motivation for the appropriate-level PCs to undertake the risk?". Screw the actual reward---in my book it's even better if the players think they are going to "make out" and end up getting hood-winked in the end. (Well...at least half of the time. Gotta keep them guessing.) It's better in a campaign if they always "stay hungry", even if they are a bit better off over time than they used to be. The have to have
problems. They have to have
unfulfilled desires and lots of obstacles to overcome---with no guaranty they will ever overcome them.
Hope, not
success, is what should keep bringing them back to your table.
There. Hopefully that stirs things up a bit. If not, I'm going to passive-aggressively insult newer editions again.