Design must be simple, ambiguous, and have 2-3 primary colors.
+1
That's why I loved that cartoony elephant of another guy/gal, who did not even submit his entry to the subreddit thread. That elephant looked many times better and it was actually close to a logo. All these entries are nice and I respect the amount of work jwcplanet put in to them, but they are not logos. Too much details, too much colors (in some, too few in others...), too low contrast, too much various insets/outsets/embeds/shadows/gradients/textures. Good for wallpaper maybe, not for logo or icon.
I loved that one too (august25, you should submit yours to the subreddit thread!). It was definitely the most polished and logo-like of them all. The only real complaints that some people had (that I didn't necessarily agree with) could easily be remedied (eyelashes, color, etc.)