So I am going to try to sum it all up:

1) I would say the biggest problem is probably in the rewriting stages. You don't have to be a perfectionist, but it couldn't hurt to be a bit more critical of your work. The good thing is you clearly have an idea of what you want to work on so focus in on execution, and specifically style.

2) Try some freestyle writing exercises. Let go of ideas and just let whatever happens to happen. With any luck this will help you develop a better sense of your own style. Try putting the characters you've developed in different places/situations; put unrelated characters into the setting you've created; write what you specifically would do were you in your protagonists shoes. These are of course very simple ideas but they may help you get a better idea of the feel for how to actually bring your story to life.

3) Synthesize, synthesize, synthesize. It isn't enough to have a style, and it isn't enough to have an idea. Truly great work comes when the two inform each other and add up to something bigger than either of them individually. It seems that you dwell on the big picture quite a bit, which is good, but it sounds like you really need to spend as much time on the practicality and application of your ideas.

If you can pinpoint the things you want to work on, let the people who read early drafts of your work know what you want them to look at. If you think you are great at the ideas, then I assume that most people's positive comments about your work will be on the ideas. Tell them what specifically you are having problems with in terms of construction, fluidity, and overall execution so that hopefully another pair of eyes will see something you didn't.

I hope some of this is helpful, and good luck to you.