I actually do this as my game plan for whenever I play as Sicily. I never could figure out the even semi-historical basis for the short game goals of taking down Venice and Milan so I instead migrate against the Byzantines and into the Levant. A Latin Empire in the Balkans and/or a Crusader Kingdom in Antioch, Edessa, Acre, and Jerusalem fuels my need for historical plausability while placing me at the center of most of the special events (crusades, jihads, mongols, ect.) that make the campaign more than just a set up for the battle engine. Plenty of action just trying to defend your boarders, and eventually Venice and Milan will come after you anyway, as they're 2 of the few factions the AI can actually be counted on to survive and thrive with, and (in my experience) the most backstabbing.
Beyond that, I never change settlement types to put me even with the AI as far as income potential, and recently I've been trying new ways to play factions, such as playing the HRE without an early blitz into Northern Italy. The hard part for this one (for me at least) is convincing Venice/Milan not to break their alliances and attack me within the first 10-20 turns. Why these "small but wealthy" "city-states" are, in 95% of my games, the most powerful, most aggressive AI controlled factions out there while France and the HRE face (again, 95+% of the time the AI controls them) nothing but defeats and economic failure is beyond me, but that's a rant, and I'm going to stop now.
I'm also now getting into a game as the Byzantines - Retake only the East Roman Empire's original former territory - which not only faces invasions from the North and West but also leaves a sizeable amount of land in the East and even South under hostile control - and hold it against all comers. Man I wish I had some gunpowder, it's a lot harder than in BI.
For me campaign changes and add-ons are the thing I'm most excited about in the upcoming expansion. I just hope we get some new diplomatic toys, special events, and victory options to play with, not just some new skinned units to kill.
Here's praying for something cool for the Orthodox factions to do, since Crusades/Jihads/Diplomacy are all pretty much out the window.
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