We usually let things have their time, unless it seems someone has gone AWOL. Then we try to find a replacement. I usually try to play quicker than this, but I have my final exams these days so I can't really have Civ at the top of my priority list.
... World Events.
Winter Storms at Sea. Sailors beware.
A young Patrician is appointed as General by the Senate.
And: "Sire, these Dacian raids will continue until we sack one of their towns."
...
Panticapaem taken.
...
Are Pirates invisible? Or is it my imagination a trade ship I has disappeared?
I vote for giving the Parthians to the AI until Techumseh returns or a replacement volunteers to take over. I think the Romans are the key protagonists of this scenario. The only downside is that this will favour the eastern Legions who can potentially exploit the stupid AI. Where which lands are left for the loyal Spanish Legions to conquer?
If we do want to have another human Parthian, we better wait until then instead of having the AI play for a few turns, they might mess up the Parthians too much, like sending their king unit into a suicide attack or some other weird stuff.
One of the reasons I could take over Alexandria so early was because the AI shipped the fortress there elsewhere. :/
Shall we play on with the Parthians under AI control? Nobody has leapt at the chance to take them over, which is a shame as this is a good scenario and they are a good faction.