I'll admit that I may be the only person in the universe who would want them but right now I'd like to see two very different things.
1) I'd LOVE to be able to use the VI keys. I've just started using vim for most of my coding but I can't do XSLT without oxygen. Never the less, you have NO idea how many times I've wanted to delete a line and typed 'dd' or '<escape>dd'. Even if its something one could add as a plugin, I'll cajole one of my coworkers (a VI demon) into writing it.
2) I would like to associate scenarios with a project. Right now, it seems that they are associated with the editor. To my mind, this makes the most sense because in one project (if its a development project at least) I'm likely to want to have different scenarios. I've found my scenarios list to get very awkward. It would probably be useful to have two sets of scenarios: project and editor.
3) I know I said two things but I was reminded of a third. I have a number of transforms that I've written that I use to fix up transforms that I'm currently working on. For instance, I create a catchall template for each mode I use, so I created a transform that runs through and checks the transform to see if all the catchall templates have been made and genearates the ones that are missing. What I would like to be able to do is turn my utility transforms into commands I can run against the current document (like the validation and indent commands). I can think of a number of different tools that I'd write that I'm probably the only person who needs.
Obviously the input document would be the document being currently edited. I would also like to be able to pass in the current selection as a nodeset.
Are you missing a feature? Request it's implementation here.