I have no problem doing diplomacy with anyone after it all kind of takes off and goes into the mid game.. The downside is, if I overdo it, it kind of looks like this after 60-80 turns.

Defensive alliance XXX
Client State XXXXXX
Trade Partner XXXXXXXXXXXXXXXXXXXXXXXXXXXX
War XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

You end up getting into so many wars with factions you will probably never see because there is like a continent of client states/allies between you and them.