Bear in mind that Crassus and Pompey are likely to prioritise distancing themselves from the second coming of Saturnius/Gracchus/Catiline over trying to plough through the remaining legislative programme of the triumvirate. Tame consuls come round every year, but a treason conviction is forever. The optimates know that as soon as Caesar's imperium ends they can get him in the dock, so they bribe sufficiently to beat Clodius in the elections for tribune of the plebs and successfully revoke the lex Vatinia because Pompey's veterans aren't in town to intimidate the voters. Caesar spends a year surveying roads in Italy, then either comes home to face the music or finds out if he actually does prefer being first man in a provincial village to second man in Rome.This is tough to get around.
This is perhaps true (though most historians put their alliance at 65BC at the earliest, so six years rather than 10). However, neither is in a meaningful office during this period: Crassus is censor and Caesar is praetor, neither of which command the same legislative clout as a consul or even a tribune of the plebs. As such, the amount they could actually achieve is pretty limited.Crassus and Caesar had been allied for 10 years before the formation of the so-called Triumvirate. And they did not achieve much together.
Though this does sort of beg the question of why he sided with the optimates and then provoked Caesar into a civil war, a mere five years after the death of Caesar's daughter broke the alliance between the two.Pompey was well aware of the immense political skills of Caesar. He knew that the optimates only wanted to separate him from Caesar in order to first éliminateur Caesar, then to deal get rid of him, Pompey.
Again, this sort of begs the question of why Caesar fought to have Crassus included in the renewed triumvirate against Pompey's complaints, despite Caesar and Pompey having had a semi-separate alliance late in Caesar's consulate, and why four years after Crassus's death Pompey and Caesar were at war. The answer would seem to be that the key alliance was between all three, that they recognised this at the time, and that each was willing to compromise in the interest of keeping the other two on board.The key alliance was that between Pompey and Caesar.
Caesar probably recruited heavily from there because it was in his area of command. The Senate raised five legions in Italy with almost no notice; they had twelve at Pharsalus (Greece), thirteen at Munda (Spain), and another twelve at Thapsus (Africa), so it's hardly the most important Roman province even in military terms. As for whether the soldiers were better than elsewhere- well, I think that Caesar, his senior officers and years of experience fighting the Gauls helped.Galliano Cisalpina was the most important of all provinces at the time. Because It was the province where one was able to recruit goods roman soldiers more than any where else in the world. It's from this province that came most of Caesar's recruits.