I like the approach. I too have battled with my fair share of ex's about the expected enourmaty of a ceremony. The justification is usually hovering around that they whole family needs to be there and that it's "my special day". I get it, we're all raised in a world where you're told that you too will be a princess for a day. Problem is that the clock strikes midnight and your sepecial day is over. Then you are left with the cleanup.

My argument will always be that things get out of hand. One relative or friend says you can't have a wedding without this person or that. Then it snowballs into a royal gala.

My philosophy is just keep it simple. If you haven't talked to them in 6 months, then don't invite them.