Sure, anything that looks vaguely like Dr. Zoidberg probably can't be TOO good, but you have to admit that the draenei are almost preternaturally nice. They're all about healing the environment, and helping the needy, and preserving the light. The undead Kendoch of Blackrock says that their goodness has really turned him off from playing one, since it ruins his suspension of disbelief.
Other posters add that the Tauren are also pretty much perfectly good, except for the Grimtotem tribe, and that the Draenei might be very nice, but the Eredar -- who are about the same thing, genetically -- have messed up the entire universe.
Another thing to keep in mind is that the Draenei are fairly extreme in their pursuit of goodness, and in the Warcraft universe, any kind of extremism leads to bad things. Humans who got too extreme in their pursuit of the Scourge became the Scarlet Crusade. Going to "any lengths" to stop the Burning Legion led Tyrande to free Illidan, and we all know how that turned out. And the Draenei HATE the blood elves -- one of their early quests leads a Draenei chief to exclaim, "They must be wiped from the face of the earth!" More than a little creepy.
I know many members of the Horde refer to Draenei as filthy hippies or goody-two-shoes, but what do you think about the Draenei? Is their goody-goody exterior true to form, or is any race that makes sexual jokes about gnomes and the Staff of Dominance hiding some naughty secrets?