Rather than use glue, you can install a nailer behind the molding (a simple piece of scrap wood nailed into the corner of the wall and ceiling).
It works well since you can now nail all along the molding.
Nothing wrong with using corner blocks at all.
Look around at some of the 100+ year old homes and you'll see that some very elaborate installs used corner blocks on both the crown and the door/window casings. Some were very ornate, hand craved too...