Stunning visuals! Amazing scenes! Visually stunning scenes of amazement!
At 10 fps.
Here is one part of WoW that I think it has gotten down almost perfectly, better than any other game I've tried, and with absolutely no unintended consequences: cartoonish graphics.
Depending on the area I get somewhere between 20 and 30 fps in WoW, excluding heavy magical events such as everyone in Stormwind casting everything they can all at once thank you very much elemental invasion. I know that's not amazing, but it's definitely in the playable range. My eyes can handle it. My brain can handle it. The simplistic graphics work wonderfully to keep system requirements, and therefore performance, in a good range.
Recently I tried Pirates of the Burning Sea, which has a bit more realistic graphics than WoW. But not too realistic. It isn't going for perfect sunlight reflecting off water reflecting off a drop of water on the hull of a ship which is splintered and burning, so don't forget the particle effects!. I like the style of it. It works for me, and for my computer. Though due to my level I've not been in any really massive sea battles, I have had some fights involving a dozen or so with no performance issues.
Not recently I tried Lord of the Rings Online, before it went freemium. It seemed fun, or like it might have been, and I've heard that the graphics are very nice, if it didn't run like crap. It goes for the realism angle with pretty shiny everything. I'm sure that's lovely for people who can run it.
Most recently I've been trying EQ2 with some friends, the sort of friends who can get me to try EQ2. It's nice and all, but 10 fps makes it a bit visually painful and really hurts the fluidity of movement. Still runs better than lotro did.
If my own experience is any guide at all to a game developer, let's try this: don't waste your budget on pretty graphics. Find a style that works, both for the theme and for the computers of your target audience. If you make a game that won't run for everyone, don't expect everyone to play your game. No level of polish, social ties, or gameplay will get people to play a game that runs like a 1920s film reel.
It won't make anyone sign up, but frankly I think devs spend too much time trying to get people to play their game. They need to spend more time avoiding the things that make people not play their game. Create a good world and people will populate it, maybe not as many as you'd like, but if you don't blow your budget on graphics, that might be fine anyway.
WoW didn't attract 11 million players with cartoonish graphics, but it did allow 11 million players with cartoonish graphics. That's one idea you can steal without being labeled a WoW clone, because it's sometimes the part that people don't even notice, until it isn't working.