Pompey isn't that overated. at the age of twenty he raised a Legionary Army from his father's veterans and went to fight Sulla. In Spain he was in a stalemate against Sertorius and that alone is worthy praise. Sertorius was a very able general himself and even his enemies praise him.

During the Civil War Pompey proved himself an able general as well, as did Crassus. Yes Crassus broke Spartacus.

Pompey was a great leader and stratagist, he was also a superb logistician and administrator. Pompey's great feat in the East was his administrative reforms and reoganisation.

As a tactician he was good but not extraordinary.

Caesar was a great tactician and leader but he lacked the other skills Pompey had. Ultimately had Pompey faced anyone other than Caesar at Pharsallus I believe he would have won.