The only logical solution to quickly deleting sub-elements in edit mode is to simply map one or more of the delete options to a keyboard shortcut(s).  Think about which option you use most often, and map it to a shortcut.  So, for example, if you wish to always dissolve edges, you can map that delete option to a hotkey.  This can get complex in Blender, because there are so many hotkeys already assigned to various actions, you need to be sure it's a hotkey combination which isn't going to overwrite an important shortcut which already exists.  Use with caution.  It makes sense to map the most desired delete routine to the Delete key, and then the X key can be maintained for the menu options as usual.  Or vice-versa.  This will certainly serve to improve the pace in your modeling workflow.

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