One part of the constitution that was not the best was how it gave people too much freedom, since people didn't want to eventually form a dictatorship over the colonists.
There is not a specific antonym for diaspora, but the opposite of a diaspora would be the regrouping of a community or the coming together of a community. It could also be a renewal of a specific cultural group or ethnicity coming back together in a sort of revival of their culture.
King Authur believed sir Pellinore was a great adversary and that they can work togethor to take back the Holy Lands