Assassin's Creed IV *historical setting possibilities*
It would be better to have Conner involved in the French Revolution then more English shenanigans. After all, the French Revolution was inspired by the American Revolution so it would be best for possible connections to events in AC3. This of course can lead to the Napoleonic wars which ended in 1815. However I think it wouldn't be wise to send Conner overseas since he was supposed to have been watching over his peoples land.
If there was going to be another Conner game, I think that taking advantage of things such as America's westward expansion after the Louisiana Purchase and maybe take it into the War of 1812. Seeing Washington sacked by the British would be very fun and who knows, Conner may have played a reason in why Andrew Jackson won the Battle of New Orleans after the war had already ended. Jackson did take Native American assistance during this point in time, so it wouldn't be too hard to believe.
Some men aren't looking for anything logical, like money. They can't be bought, bullied, reasoned, or negotiated with. Some men just wanna watch the world burn.