First, please vote what you think. That is KEY. Only thing is be prepared to defend yourself in some well intentioned and good natured (it better be!) discussion. We can be passionate about some things and many of us have personally established systems of rating things so if somebody disagrees with us then we want to understand why.
((I got on a soapbox so don't think that the rest is specifically directed towards you, wildcorn. Just general thoughts aimed at anybody reading.))
I like to think my number one criteria is common sense. If you can justify it in a reasonable manner than that goes a long way. You don't have to have every angle covered but make sure that it doesn't raise more questions than it answers. Most of the time this takes care of itself on accident, but when things don't make sense or a contradictory then they stand out. The balance issue reveals itself here as well.
Creativity and uniqueness. One or the other and especially both goes a long way. The problem is most people think they have something unique or creative and find out it may not have been. This might be more of an experience thing because if you haven't seen it, how do you know it is a cliche. New posters (gamers) hurt here the most. They often go cliche and uberpowerful because they haven't got the experience with it and we can't entirely blame them, just hopefully we can help them with it.
Inspiration If it passes my common sense test and it is creative or unique I go on my gut and how many ideas get generated as I read it. If it is something that I am constantly ohhing and ahhing about as I read because I can think of so many situations and ideas I can use this submission in, it goes straight to the top. If I read it and don't get that warm fuzzy of idea generation then it hurts a bit in my estimation. A three (3) to me is just something interesting that I could use but I probably wouldn't.
Now, some may be written dry and boring, but if you look past that on some of them you can see the solidity of the submission despite that. My personal preference is actually short and sweet, just the facts ma'am. Because that is all I need, I will usually want to fill in the rest myself to make it fit into my game and/or game world. Cut the fat, give me the meat. If it is good enough then I will only take a small part of it and then put my own spin on it, if it is really good then I might only change some of it, but I doubt I will use anything specific that is written in it, I still take the core idea and make it mine.
BUT, I would never vote down anything that went more specific, detailed, extended, as long as the key idea is still in there and is still solid. The rest is dressing that might add to the entertainment value but doesn't add to my ability to use it usually. Story never hurts, especially if I can't use the submission, because then often times the occassion to use the submission is demonstrated and makes it more apparent how it is intended. Then it will help me understand it better so I can have a more educated vote than a dry bones submission may normally give me.
That is my spin on it and you will (hopefully) get a different spin of some sort from every person on the site. No one person's opinion is more important to anothers. Each person's opinion is valuable and appreciated. Agree with those you agree with and disagree with the others. I can see the need to try and accomodate the Strolenites, but I hope that you can still do your own thing the way you want to and don't let us sway you too much. Any idea, regardless of the rating, is important and I am certain has helped somebody. Don't let lower votes get you down. Take the votes and advice and move on. If you want to feel better go look at my oldest posts. Yes, I am embarassed of them but they are me X years ago just starting the site and that is what I did then. I leave them there because that is all me, no denying it. I have learned from them and there are still some ideas in there somewhere regardless of their unpolished form. I still have a long way to go compared to others. I am happy with my occassionaly good posts and comfortable with the ones that people don't like so much. Everybody starts somewhere, some may come with a bit more experience than others but I hope that anybody can feel comfortable enought to give the place a try.
Don't give up! Keep submitting and you will find your form and we will respect you all the more for toughing it out.