It would be a nice future if an issue can belong to many different projects. I don't mean duplicate of issues, cause this still exists.
A concret example: We have customer projects which consists of different software modules. For each customer project this is different. So if an issue in a customer projects is reported and one see, that the bug is in module xy the issue will be assigned to all other customer projects that use the module xy. With this, every manager of the customer project can see the status of the bug in which he is interested in, in his onw project.