I would say you are right about Croatia specially on the Islands near Split (central Croatia). Much less crowded on the North Croatia, along the coast and in the South.
Regarding Greece it is a lot less crowded, you don't have to pay for buoys (you can anchor everywhere) along the coast is not crowded and even on the Islands you generally can find always a place. I have been several times the only boat in an anchorage, even on Islands, In August. You just have not to follow the crowd.
In between you have Montenegro, you can anchor everywhere without paying, it is less crowded than Greece, I would say not many boats considering August, and live is cheap. Excellent food and wine