If I think of him just needing to be a bit better than Kennedy, it is a win. It will not be hard for that to happen.
I guess this is a glass half full or half empty issue. Kavanaugh will probably be better than Kennedy but not a Scalia-clone. If you compare Kavanaugh to Kennedy, it will be seen as a win but if you compare Kavanaugh to the Scalia-clone nominee (who couldn't get approved and might not exist anyway) then you will see this as a lost opportunity. Personally, I look at it like you do. We shouldn't let the perfect be the enemy of the good.
Trump would give us a better justice than anyone currently on the court other than Thomas and maybe Alito and Gorsuch. I wish Justice Thomas the best of health and a continuing desire for a long, long career. The court will inevitably move to the left, to some degree, when he is replaced. There are not many judges to the right of Clarence Thomas and even fewer who could get approved by the Senate given a sure solid Democrat opposition and a few squishy Republicans.