There is a lot of interesting features to be implemented (on http://www.softwareideas.net/RequestTracker/Index/2 and much more in my private list of improvements). If it would be possible, I implement all of them immediately, but it needs some time. So I work on new features gradually and add them step by step.

DPI bug was fixed in version 7.30. Is it not working for you?

Copying using CTRL and drag&drop can be added soon.

Duplication as you want it is kind of versioning, it has larger consequences on whole applicaition and it is quite big feature if I want to implement it properly. SIM is not just a drawing tool it has a model of whole project and its elements on background and it make things (for some features) more complicated as it may seem at first sight.

However I can add (as I mentioned earlier) a Duplicate menu item to the context menu in the project tree, which duplicates a selected diagram (and add it on the same level in the project tree as the original diagram).