Depends on the developer (and its size). Technically I'm a producer with a game developer but I also do design, QA, support, graphic design and web content work (probably far more than any actual production). You'll find that job titles at developers rarely fully encompass the extent of people's contributions.
Likewise, even a "dedicated" producer on a project has a lot of creative control through influencing other people on the team that do have more authority, making suggestions and improvements for titles, getting involved in business and management decisions, relaying feedback between departments and individuals, and so on.
Ubisoft is a big company, and therefore often individuals "in the trenches" have less control than at smaller studios... but on the other hand, I expect a high-level producer there has a lot of control over the outcome of a project.