When I created a simple find/find next action, I found that changing the selection in the editor was insufficient to locate text in a time-efficient manner. It would help if the editor module had a method to jump to a particular line in a file.
Other types of actions could use this feature, such as a wrapper for pdb that could serve as a debugger, or one that simply allows the user to browse a file by line number.
Access to a search box would enhance the experience as well, but isn't as fundamental.