Ok. Thank you for your answer.
I can understand: there are certainly good reasons why Orchard is designed this way and one day I will understand all of them :-)
For now, let's talk a little about this blog post rendering. So, I have a basic Orchard installation with the Blog recipe and the default theme.
1. I create some posts.
2. They are correctly listed in the /blog section of my site.
3. Now, I'd like to style/position/render them as I want.
4. Ok, I rewrite the Content-Blog.cshtml view with Shape Tracing tool.
5. Great. Now I can rewrite the output of every element in the loop of the posts!
6. All I wanna do, now, is structuring my post. Using template overriding? Sure. Using placement.info? Why not? I don't care, since I can't do it in any way, so I can't decide what's better! :-)
Excuse me my talking style, but really, I'm going crazy. On this message board, at least 50 people asked my same question, but nobody seems to be understanding the real problem and so there are no answers. I think there is a curse or something about