Not necessarily. A novel or any story is so much more than sentence structure. You need to know how to picture things, what images to use, what words that will convey the thing you're after, and so on, and often you wouldn't know the effect of your efforts until you read it through afterwards. = after having finished that first draft. So It's quite possible to have loads of rewriting to do even though the sentences are well structured, because maybe those weren't even the right sentences in the first place. Maybe you'll find out when you read it that they don't make the story come out the way you wanted it to. To answer the op: I don't think much of sentence structure during that first draft, I just focus on telling the story the way I see it in my head, trying to make it justice. Sentence structure has never been a problem for me. It's just there, forming sentences as I write them.
That sounds more like a case of indecisiveness to me. If you're writing sentences and then realising they don't match on a reread of your own work then you're failing to get into the whole psyche of your characters and the atmosphere of the scene itself. There is two sides to sentence structure: 1. Making the sentence convey as accurately as possible your desired story. 2. Making the sentence as clean and articulate as possible, so your work flows in conjunction with the body of work. I'm not saying that people who revise as they do wouldn't still have a lot of work to do on their second draft, but from my experience, I've found that you are cutting and rewriting a hell of a lot less via this method.
