Ultimately, it'd be best if that window could be cut out and the user returned straight to the thread, possibly with a temporary yellow "Post updated" bar at the top or something so that they know that their change has been applied.
Probably or possibly. Can't say I have strong feelings about it, but I can understand why some might feel it gets in the way.
Yeah, that'd work. It would save us all a few precious seconds.
I've wondered about this myself.
Not that it's a glaring flaw or anything, but it does seem that it could be dropped in favour of something on the thread page saying the thread was updated with your post/edit.