Fears of a Newbie

My newest book should have strong writing, but my writing isn't very strong. In fact, it's weak and about as subtle as a blowtorch to a snowball. I could never make the theme stand out without actually preaching it, even though I have several scenes that if done correctly, would be powerful and pull at people's heartstrings. If done correctly. If done correctly, my story would have a political stand about race, but I don't want to be political. It's just that one of the characters happens to be a different color than the rest of the group, and people would point that out, and if I don't mention it at all then I'm not doing the story any favors. It's also part of one of the character's major motivations to protect this person because of the prejudice she receives. So, it's actually quite a big deal.
The characters each have a lesson to learn and, if done correctly, could reflect common life problems. They could resonate with the reader. The characters could grow and become better for it. Readers could learn right along with them and feel like the book is worthwhile, something worth reading again. The adventure is a bold undertaking, one with great stakes that rise from the littlest problem to near death experiences. Someone might even die, and it would break my heart. Would I try to engineer a way to bring them back to life, or would I resist the urge so that the pain stays where it's supposed to be? I know better than to have a contrivance such as that.
I know better than to pander to my readers. I know better than to pull any punches. I know all of these things from all of these writing books that I would never make a huge mistake. I think. The ins and outs of a story, the type of outlines, the types of stories, eight, ten, twelve, twenty, however many there are. I mostly know my grammar except for the really tricky bits, so I could never write a long, beautiful sentence that breathed itself to life and kept breathing until the reader was breathless just for following through. I don't think I could ever be coy, or humorous, or wicked in my writing. No, I just don't have the skills. Really, it's a shame. Because I have a big, gorgeous book that I want to write and I simply can't.