Deleting of items should also be possible with a short cut key combination - not only removing the items from the structure
Preferably without requiring an acknowledgement. The aim would be to mimic the speed of mind mapping tools for capturing information in meetings. One of the issues is if one wants to delete a item it should be as fast as creating one
This is a good idea and we try to make JIRA as easy to use as a mind mapping tool.
But a feature that makes it possible to delete an issue with a single keyboard shortcut absolutely requires Undo. However, an issue is a lot more heavy-weight object than a mind map node and deleting an issue in JIRA is not undoable. So I guess the best we can do is to collect removed issues in the Trash collection and then let the user Bulk Delete them through the standard JIRA interface.