I'll have to read up on the campaign to get a better feel for it, but I read Rommel's
Infantry Attacks before the weekend, so it's pretty fresh in my memory. I'm not sure a greater German victory if that feasible. In OTL the actions of the Austro-German forces were mind-boggling. As Steffen mentioned above, Rommel's own detached force of a few hundred took 7-11,000 prisoners. But they were engaged in constant fighting for a period of several exhausting days, and there's only so much the human body is capable of. The German offensive, I've seen it said, was stopped not by the new Italian defences - though they certainly prevented later offensives - but by the incapability of the Austro-German troops to advance faster than the Italians fell back.
Just glancing at the
Wiki demonstrates the problems facing the Central Powers.
Italian losses were enormous: 275,000 prisoners were taken and 2,500 guns captured; 40,000 were killed and 20,000 wounded. Austro-German forces advanced more than 100 km in the direction of Venice, but they were not able to cross the Piave River, where the Italians (with substantial help from French, British and American allies) established a new defensive line, which was held for the rest of the war.
The Central Powers employed 35 divisions against 41 Italian divisions. But the prisoner situation was
ludicrous. Rommel recounts having just two sentries available to act as Guards for fifty Italian officers, and being worried lest they should overpower the guards. But this isn't the only problem. Remember the '14 attack on France's failure was in part because the railway and road system simply couldn't cope with the demands laid on them. Think how much of a bother one has when a quarter of a million prisoners need to be properly guarded and moved out of the combat zone. It's a nightmare for any logistics officer trying to move men and supplies up to the front.
These are just my initial thoughts. I'll have a skim over some more info on the campaign and be back later on.