3d cinematics too costly, Civ 5 style pictures + music is more appropiate.
this.
Not to say copy Civ 5, but could be nice.
start with major events, then scale down from there if you wish.
Examples:
discovery of the new world
First colonial nation
start of the Christian reformation.
Start/end of hre league wars
Passing imperial reforms/forming the HRE/greyskin
When your country finishes westernisation.
when your break free as a colonial/vassal/PU nation.
when the first revolutionary nation forms.
ending the game in 1821 "winning"
losing.
going into bankruptcy.
Becoming a new tag/country.
Unify Islam.
Mending the schism.
World conquest.
woah that's a lot of work! Bet it would be great!