I think that, in order to succeed, several things have to happen.
Short term:
-Caligula (while still alive) has do something pretty stupid to upset the populace
-The conspirators need to take out Claudius as well.
-Some key officers need to support the coup, especially within the praetorian guard
-Cassius Chaerea needs to be one hell of a public speaker
Long term:
- The conspirators need leaders as virtuous as Cincinnatus, as eloquent as Cicero, as skillful as Octavian and as popular as Caesar
- A lot of compromises and reforms have to take place
The last two are, IMO, pretty hard to pull of, although not impossible.
Just my 2 cents