A few little suggestions that might come in handy. I know you guys are busy as busy can be, but maybe they can go onto item #235235 in your TODO list
1) Replace object: A few times I've switched from one sprite like EnemyA to EnemyB, but I have to go through every event one by one and change the object. Usually I just revert to using wingrep on the xml files and manually do a find+replace. Having a "Replace object" on multiple lines in the editor would be super handy.
2) When creating a new object family, when you add a sprite with it's own instance variables it does not get added automatically to the family. If you try and add the same variables you get a conflict, or in the case of behaviours you end up with a duplicate. In this situation again I find it easier to just jump into the .caproj and edit it manually, but it would be nice if the IDE could do this.
3) When undoing, I see "Added Action", "Changed Variable", "Pasted Action" and so forth in the corner of the IDE, but I have no idea where that is taking place. It would be fantastic to be able to click that text and actually jump to the event sheet and line that took place.
Like I said I'm not saying you should guys should implement these right now, just maybe some little things to add one day when you have some downtime.