Ticket Workflows as independent entities.
This is a feature I proposed to TRAC for the 0.13 version that will allow managing multiple projects and subprojects (http://trac.edgewall.org/wiki/TracDev/Proposals/MultipleProject#Workflow) . As Redmine already have this feature, I think it could benefit from this idea as well :
Currently, ticket workflows are managed once for all the projects (or hierarchically if I understood well?). The problem with this is that it's hard to have at the same time separate specific workflows for some special projects and general workflows for several other projects.
Hierarchical organisation, like inheritance in some cases, don't solve correctly this problem. As often, composition is a better choice.
The idea would be to "give names" to workflows, making them separate entities that would be editted separately from the projects. Then for each project, the manager would just have to set a workflow (in a list) for the project, maybe using this workflow for one or several projects. Workflows should be isolated.
A separate edition of workflow would allow the user to have the hability to define state transitions between different workflows, maybe by setting explicitely wich state in workflow A correspond to witch state in workflow B and what would be the default state if nothing is explicitely stated between two workflows.