So you're saying if you're young and just starting out, you should choose style over substance? That probably won't go real well at the film festivals for the critics.
Everyone's got their own path and I haven't suggested a single thing to anyone. That's just my path.
I realize that an unwatchable movie is an unwatchable movie, no matter how great the content is. So, I focused first on learning how to make something watchable and interesting, and by telling basic stories that everyone understood.
Film Festivals and Critics? Well, the former will take something more competently strung together with less substance over something that's unwatchable but rooted in heaps of substance. And, critics? They don't really dictate sales in any way shape or form.
See: Transformers franchise.
As far as style goes, see Edgar Wright and his path toward "big leagues". I'm not saying he's ALL style, but his style is fairly recognizable and as an auteur, that's part of why he's a recognized and working director. He has his own very distinct style. That's what I believe.
If you're a young filmmaker trying to break into the business, which script would you choose from to direct, if you had the choice? The Shawshank Redemption or Mortal Kombat? Which is more likely to be better in most audiences?
Mortal Kombat, easily. Why? because I understand the content. It's stupid, brainless fun, geared toward my demopgrahic. And, it'll sell. Which means I'll be able to make another movie regardless of how bad it is.
However, Shawshank Redemption is one of my top three favorite movies, right beside GHostbusters and Primer (there're a lot of difference in each). I know for a fact that I cannot handle mature content like Shawshank right now in my life. I am too young and it would come off very pretentious, sappy, or more than likely have the incorrect tone.
Again, though, that's just my path having been doing this for a while. Style is much easier to cultivate than substance, which comes with age.