I knew that VIM was an editor, but I hoped I could turn into powerfull IDE as many articles suggested. I was wrong unfortunately.

You were wrong, obviously, but the people who made you believe that with their stupid blog posts are wrong, too. I'd say they are more wrong than you.

Those blog post are seriously misleading: at best, one can come up with a vim config that make it look like a stereotypical IDE: file tree on the left, class tree on the right, quickfix at the bottom, completion… But there's a lot more to an IDE than that. Because Vim will never understand your code as an IDE does it will never be an IDE, full stop.

It can be the (super charged) editor module of your development environment but it would take a lot more than a blog post with cool screenshots to explain how and why. Even this 7 parts series is probably not enough: http://blog.sanctum.geek.nz/series/unix-as-ide/