Was there another point in history where the control of Malta heavily influenced the outcome of a war as it did for the British during the North African campaign of WWII?
I'm primarily interested examples from antiquity, but any time period (Crusades, Early Modern, Napoleonic) would certainly be interesting.
Well yes actually, there is a reason that the Italo-German efforts are just A Siege of Malta, not THE Siege of Malta.
The single time when more rested on who held Malta than at any other time would be the Great Siege of Malta in 1565. When more than 20k Ottoman Turks and their allies spent 3 months trying to root out 500 Knights Hospitaller and tier 4k or so auxiliary and soldiers.
The Knights had been cast out by the Turks a generation before from the Island of Rhodes, and their resurgence, and counter raiding of the Barbary Coast had finally drawn Suleiman the Magnificent's attention once again. However this conflict was very much a proxy war against the Knight's backer in Phillip II, the reigning Hapsburg monarch and the leader of the general Christian effort against the Ottomans.
This was very much on the backs of an age of Ottoman ascendancy, less than 100 years since the fall of Constantinople, Suleiman had even gone so far as to lay siege to Vienna previously before being checked. And firm control of Malta would aid in his efforts against the Italian city states, and the hated Hapsburg's, while even the French at times flirted with parlay with the Turkish forces.
For 3 months Turkish guns and forces blasted at Forts St. Elmo(which they did capture at great cost), and Fort St. Michael and Birgu. While inland Mdina held out to harry the invader's rear.
Finally with their morale sapped, strength whittled away and disease setting in, a reinforcement expedition from Sicily arrived and cast out the Ottoman force.
Thus Suleiman was checked again in his attempts to capitalize on earlier victories. Thus he turned attention soon to the Venetian held island of Cyprus. This would force the Pope to call a untied Christian League, under the leadership of Don Juan of Austria(bastard half brother of Phillip II), and to meet the Ottoman fleet in 1571 off Lepanto in Greece. Winning one of the final galley battles, and the first Ottoman naval defeat of size in 100 years.
Crowley's Empires of the Sea: The siege of Malta, the battle of Lepanto and the contest for the center of the world is a very good and readable introduction.