[davnicwil]

> Why shouldn't I call my branch for integrating code... integration, or something?

You can :-) gitflow is just a pattern, the names of the branches are an implementation detail. Just using develop here as it's the name used in the parent's question.

> A very typical scenario is when a new dev joins the project, hacks happily on branch forked from master and finally submit the PR with fixes which were already done..

Gitflow like any branching strategy requires that people using it understand it first, to work. Obviously it's always better to craft these things in ways which help people fall into the pit of success, but if you have new devs just cloning a project, branching however they assume is ok and then fixing bugs that others are working on etc, without once asking a question or being instructed in even the simplest way on what to do (saying 'we use gitflow on this project, development branch is called X' in the readme for example), that's a problem that no branching strategy is going to solve!