I think it would be a good idea if you could rearrange the order of effects and behaviors. Currently the only way you can do this if you've already added effects/behaviors in the wrong order is to delete them and then add them again but stacked differently. This causes problems, especially with behaviors such as the bone movement, where you'd have to recreate all of the animations if you had to put another behavior behind it. So I think it would cool if you could just drag them to rearrange them.
I agree, it can be quite annoying having to delete and recreate effects and behaviors, although I've never had to delete something I've spent ages on, I can see why it could potentially be a problem. Drag and drop stacks would make things easier.