I suspect - and hope - there won't be an American War of Independence etc per se. However, they would be semi-random revolts rather like the Baron's Alliance in the Kingdoms Britannia campaign. It seems that major colonies have a tendency gradually to break away over time - admittedly many after the Empires Time period - and I think CA should factor this in. May be have some factor like distance from capital that causes unrest and have it slowly ramp up over time. When the home country is weakened by a foreign war or raises taxes too much, colony unrest may hit a critical level (not observable to the player) and bang! all hell breaks loose. A new faction could be formed - American rebels, whatever - and gradually get reinforced by newly spawning armies.

The French revolution is also interesting. Again, I'd prefer to see it modelled more generically and semi-randomly rather than - like the Mongols in M2TW - always happening in the same place, in the same way. I understand there are government types in the game. Perhaps the more authoritarian could gradually become more problematic over time, to represent the spread of liberal and democratic ideals. So an authoritarian leaning British player could face a French Revolution type uprising - it would not just be confined to the French (Peterloo and all that). Ideally, there should also be a chance of nipping a nascent revolution in the bud - as in 1848.

It would be a bit lame if the British player knows in 1776 or whenever, he has to be prepared to squish a major American revolt; or the French player is forced to change government type at a fixed time in the game. Better to allow for alternative histories and keep players on their toes.

I would keep scripted deterministic historical events to those that are more minor and external to the theatre, and also to technological improvements (industrial revolution? rifling? skirmisher tactics?).