I agree that the Sardinia option is a valid one - after Sicilly. Before, though some did at the time advocate in - e.g. Mountbatten, but Sicilly has the space for airfields.
The trouble was, it wasn't agreed early enough what to do next. And when it was agreed - when the battle for Sicilly was over, it was too obvious to the Germans where the Allies would land.
Topographically, the western side of Italy was the worst. So 'fix' the German attention on Sicilly, with a slightly lower scale invasion (Montgomery) - secure space for airfields, a right-hook to take the heel of Italy (Patton). Who crosses to the west to block evacuation from and reinforcement to Sicilly, while a follow on landing at Brindisi (?) a small Italian Naval Base north of Tarranto - ultimater objective air bases at Foggia. But with the Allies on the East coast, a greater success at Sicilly, now an opportune time to go for Sardinia - French troops, to be followed by Corsica.
Now, the Germans won't have a clue where the Allies are going next! To South of France, for Rome (by-passing the worst terrain), further along the eastern side of Italy, or across the sea to Yugoslavia!!