First of all, where is this planned to be used? What's your target audience? Is this for kids in a forum or discussion board? Is this to review products? Is this intended for management levels in a corporation? Is this for western culture? Eastern? How do you plan to convey neutral statuses? What if I don't like the post or whatever? What if I find it utterly offensive? Should I use a sad icon when it got me mad? Did you study legibility of those icons? Are these the actual icons you plan to use?
See, using mood icons is not a bad idea in itself, but you'll need to be very careful with all aspects, from design to semiotics. Your icons needs to be unmistakably unique, legibility has to be perfect at any size (hint: try SVG) and the mood your icons transmit has to be the correct one. Keep in mind connotative meaning is hard to achieve amongst different targets.
But well, try it, test it and see what happens. As I said, the idea is not bad, just problematic
PS: if you REALLY want to dive into semiotics, try this article to start understanding the complexities between Eastern and Western cultures in language. And you'll be just scratching the surface!
EDIT: Now that I see your edit and the mockup, I see what you mean and barring some geo considerations, I think it's good, exception made of your last icon. To me, it looks like "shocked" rather than "great!" (see what I meant?).
Besides, it's always a good idea to have an odd number and at least 5, because your 3rd icon would be a middle point, your 5th icon the best, and the 1st one the worst. But what if I want to give an "above average, yet not perfect" or a "below average, just not horrible" review?
In short, try to provide at least 5 icons (and choose them in a way there's no room to interpretation)