My first lucid dream was pretty vivid, but once in a while I will have one that is very blurry or very dark. It's probably just chance that yours was a blurry one. Sometimes if everything seems hazy I will stop, look around, and just take everything in; it seems to increase the vividness.

Also, it may have something to do with your induction technique. I'm sure it's different for different people, but I've only had one DILD that was kind of dark, but quite a few of my WILDs were blurry or dark. When I first started having WILDs this happened a lot. Sometimes they start off blurry and then turn vivid.

I wouldn't worry about it too much. Looking back on it, I've had so many drastically different lucid dreams; many were satisfying and some not. It's only a matter of time before you have your first satisfying one.