This topic is the center of the discussions of the old Waterthread and it was one of my points when I commented World of Warcraft.
From my point of view the situation isn’t complex, there’s a key to “read” it. It depends on where you place the “aim” of your game. In DAoC the PvE is a grind and a treadmill because you want to reach level 50 and be able to join the RvR. So it’s a duty.
It’s about this simple concept: the treadmill is the aim or the consequence of another aim?
Let’s take another common example, Diablo 2 (I know only the first levels of it). As you move through the world you explore the map, kill monsters and gain experience. In this gameplay, if the game is well balanced, the levelling and progression of your character will be tied to the treadmill. As you *do stuff* the character grows.
The fun is in this concept. Till your aim is *doing stuff* you have fun. When you *do stuff* to reach another aim the fun is being killed. And you have the grind part.
I think this is a more simple and precise definition of the fun/unfun aspect of a treadmill. As Ian Reid says, everything in a game is a treadmill in the end, so you need to figure out where it achieves a negative value.
I pointed this value.
When you have in your mind a precise idea of this dynamic you have also a clear vision of how the gameplay of a mmorpg should be developed.
There’s a discussion about this here:
Cause and consequence. If the treadmill is a consequence (side-effect) you have fun, if the treadmill is a cause the fun stops and you have the grind. You can monitor what happens on a play session and you’ll see where the treadmill lags behind the aim and becomes a cause (grind). It’s a change of focus. From doing concrete things in the world, to repeat algorythms toward your personal power-grind.
At this point you finish on another new level. On this level you need a “term of measure” to monitor when an experience is a grind or not. This term of measure is about learning. You’ll discover that when you learn something the process is fun. When your actions loose the learning process the game fails and becomes boring and unappealing.
Dynamic learning is the only heart of this issue. The learning is the only element involved in the treadmill and it’s why this treadmill can be fun. If a process doesn’t include learning you obtain frustration and alienation.
This brings to marxist theories and I think i’ll stop here :)