Agreed- No planning for this. Overlord required an immense amount of planning and allocation. Not done in 1943
Fewer landing craft, but if you can fake operation in the Med you'll still have some.- No landing craft
Yep.- Too few troops
Actually they'd have had Valentine DDs in time, if nothing else, which might have been okay, since although they were outdated they'd likely have been facing only very light opposition.- no specialised armour
Agreed.- No harbour
But with defences only around the harbours, and lacking- Germany in a better shape
No air supremacy, but they'd almost certainly have been able to gain superiority when and where they could put aircraft.- no air superiority
Thing is though, Sicily is in a very important strategic position, so the Allies will go after that first simply to secure safe passage through the Strait of Sicily, and then you can think about where to head next. Also, once you have Sicily the obvious next step is Italy proper, which is useful assumption for the enemy to make if you actual next step is Sardinia.
German tank strength in June 1943 was something like this:
26th panzer had 77 tanks, only 14 of which were panzer IVs.
24th panzer had 24 tanks, 4 of which were panzer IVs.
14th panzer had 19 tanks, none of which were IVs.
9th SS had 3 Stugs.
Most of the non-Panzer IVs were captured French tanks or Panzer IIIS. For infantry and artillery strength only 24th a Panzer division was in reasonable shape with 11,000 men; the rest were basically a few thousand veterans plus whatever replacements they could receive. Most guns and prime movers were a mix of obsolete AT guns and captured artillery. Infantry divisions were in even worse shape; most were recent conscripts with obsolete artillery and next to no mobility.
The real nail in the coffin is that 26th and 24th Panzer, the only "strong" German divisions, were held deep in reserve. Movement will take several days with very few horses or trucks available, allowing the landing to secure a significant lodgment which would include Caen and Cherbourg. After that the Germans are caught in a battle of attrition which they will lose very quickly.
And remember, the Sherman's still pretty much the best tank around at this point. It's got a gun comparable with the workhorse tanks of other powers, there's no Panthers to mess it up, and it's the most reliable thing on the planet. In other words, the Allies (for once) have the qualitative advantage in tanks.