I was going to say that's a lot of vinegar, but it's also a lot of sugar, holy cow.
I like bitey food, so I would probably reduce the sugar and put some oil in (walnut oil likely). Lots of variables: not all white balsamic is the same, some is more acerbic than others. Not all dijons are created equal either.
But when in doubt, add salt and see if it does the trick.