"nice" is understatement for anyone doing debugger coding with pharo . The lack of refactoring tools was a main reason I am not coding solely inside the Debugger so its definitely great news.
My thought about Pharo is two sided one "Modularisation" and "Documentation" . I can think of no more important coding concepts. In the case of refactoring tools, it would be nice if refactoring tools could define a common "protocol" that any IDE tool could use to take advantage for them, so one would not need to hard code them inside the individual tools. Maybe that is already possible to an extend I have not looked into the code.
If memory serves me correctly Debugger was modularised separating its GUI side from its core model.
Personally I find Pharo extremely powerful when it comes to refactoring already.
The one thing I would change is make the menus more intelligent, right now you can do illegal actions on selections for example I can inspect part of a message which of course it returns an error, it would be nice if the menu entries were disabled , grey out or removed in case of a bad selection, or ideally auto-correct the selection so the menu command can work.