If the allies had landed on the coast on Croatia and marched through Yugoslavia ,into Eastern Europe and invaded Germany itself from the east the allies could have saved many countries from falling to Communism If the allies managed to trick Germany into thinking France was going to be invaded the success of the Balkan invasion would have been greater as the Germans would have concentrated a large amount of there forces in France.
Stretched supply lines, limited air support, mountainous terrain of Balkans, and most importantly stretched supply lines. Plus the goal was to destroy German manufacturing.
How would you be tricking the Germans that you are invading France, when the invasion fleet is sailing westward across the Mediterranean and up the adriatic?