It isn't demotivating to me to not have people test, but it does slow things down. Right now since I'm the tech builder and tester, I see things from just my point of view so I can easlly miss something. But more sets of eyes catches bugs faster.
And remember, my personal opinions about testing are different. I don't "play" wow. But Ive found that to make a game great, listening to the tester feedback is key. don't feel like all you have to do is report bugs, If you think of a better way to do it, and it works it will go in game.