Depends on your definition of arbitrariness, I would say... I'm just saying, *IF* you run Sicily badly, *THEN* you should see Garibaldi starting to raise hell.
Given that most of the time Sicily will be AI, and probably badly run, we should see Garibaldi most of the time. Otherwise we will see revolts in Sicily all the time, and ask ourselves, where is Garibaldi?
The possibility to see historical figures make an impact is IMHO what sets Victoria apart from a long-term sandbox game like Crusader Kings or EU3 where it would of course be silly to see Michelangelo or Gustav Adolf to pop up 100 or 250 years after the game was started. But a game which starts at a point where most of the historical people are already around should have those people.
Age of famous 19th century people on 1/1/1836:
Guiseppe Garibaldi - 28 years (already a seasoned veteran of the liberal rebellions at that point)
Otto von Bismarck - 20 years (already finished law studies, already strongly conservative, already in the Prussian civil service)
Abraham Lincoln - 25 years (already a member of the Illinois House of Representatives, and about to hold his first anti-slavery speech)
Isambard Kingdom Brunel - 29 years (working as chief engineer of the Thames tunnel in London)
Don't cull them all! The game would be so bland without them.