Lately I enjoy thinking about how to streamline games like WoW even more. It's partly an ironic endeavor, and partly quite interesting.
For instance, let's look at item progression systems. WoW uses the typical str/dex/end/hit/crit/... kind of system. It has already been streamlined a lot. Nowadays you can safely assume that any item with a higher item level is a good choice. There's a bit of reforging going on and you can min/max a bit, but most players just go for the higher item level.
Blizzard wanted it this way. They didn't want players to encounter a complex world that has not been fitted to their desires. They believed the forum posters who cried: "My chest has too much str and not enough dex, stupid Blizzard!!"
Now, if you ignore the bit of min/maxing, that only a few would describe as 'interesting decision making' anyway (you just load a web page to optimize your gear), we can indeed streamline this system without losing anything; and gain a lot!
Instead of increasing character power by increasing an item level, then calculating attributes for different speccs and then balancing it so that each specc does perform similarly, we could just increase the character's performance (dps, hps, survivability) continuously with the item level.
The attributes were severed from their simulation-roots long ago, anyway ("Oh, you are 2531 times as intelligent as I am, interesting!"). We gain a system that is very easy to balance, because everything depends on just one 'attribute', the item level. You gain item level to become more powerful. No designer has to think about e.g. which rotation profits more from str than from dex and how to balance accordingly.
On the other hand, this shows the trouble with Blizzard's purely iterative approach. Without a long-term vision for your game, you run into problems like this. It's like a slightly flawed local optimization algorithm working on a very complex game design possibility space with the vast majority of local optima not even near the global maximum. You might end up in blind alleys.
This, by the way, applies to all complex systems. It is no coincidence that one of the least flexible political systems has been one of the most successful in recent centuries. Regarding MMORPGs, as well as regarding political systems, it is important to understand that most things that seem good at first glance turn out to have serious side-effects.
What is problematic, of course, is if the environment starts to change. If the speed of technological change becomes ever faster, the optimal balance between conservation and progression is changed, too. I fear that's the root problem of many political systems today.