In Redmine the central part which defines the workflow of an issue is the tracker. It's the same for every project. If you want a different workflow you will have to create another tracker for that. It's very likely that if you have different workflows in different projects, your kind of issue is also a different. So it makes sense to track different types of work separately.
I'm closing this issue by now, as I think this is more a support request than a feature request and therefore it should be placed in the forums as described in Submissions.