Well, you might avoid the Franco-Spanish Union, although recent interpretations have downplayed Eugene's role. I doubt anyone else could have beaten Marlborough at Blenheim, but France simply had enough resources that it didn't need a victory at Blenheim alone. Besides, the Austrians were already falling apart.
Of course, he was somewhat over-advertised. Louis had other highly capable generals like Villars and Vendome (who guaranteed French dominance in Spain). As for Blenheim, it should not be forgotten that at this battle Villars acted as Eugene's 2nd in command (they were close friends which prevented quarrels which often happened in Louis' army when command line was not clearly defined).
The Austrians, as you correctly noticed had been pretty much falling apart, which is not a big surprise taking into an account that their salaries had not been paid. Their best general, Louis William, Margrave of Baden ("
Türkenlouis") was at odds with Marlborough (not a big surprise, taking into an account that Marlborough was trying to play a boss and and Louis William with his impressive list of victories considered him an annoying puppy with no military credentials, unimpressive pedigree and repulsive moral qualities) their quarrel was one of the reasons for allied defeat at Blenheim because at the critical moment he flatly refused to send Imperial Cuirassier brigade to support Marlborough attack.
While, of course, as you said "didn't need a victory at Blenheim alone", this victory was quite important not just as a battle won but also because this was a beginning of alliance' breakdown: the Brits and Austrians kept blaming each other, cooperation was pretty much gone and the conflict deteriorated into a number of the separate wars (Brits and the Dutch in the Netherlands and Austrians with their allies on the Rhine and in Italy; in Spain the Brits just sailed away with a resulting capitulation of the Austrian contingents).