If your doing total war mode, Pontus is hard as fuck its more or less instant wipe. Seljuks while looking cool, presuming you have to disband their vassals could be hard also.
Oh you mean hardest campaign possible? I meant hardest campaign that is actually on youtube.
Even without clients, selecuid start is huge and they 100% have the best unit roster in the game. So I think I could do it pretty easy in total war mode.
I think Pontus would be harder in total war mode than epirus. But its just a matter of searching for a starting stratergy that works, think I could find one.
I've actually did some "this is total war" campaigns in old patches (which was alot easier). And I know its possible to do:
Lustinani (relocate to africa)
Nervii (relocate to britain)
Baktria
Iceni (easiest)
Sparta (relocate to africa)
But relocate stratergies aren't as fun, and niether is sitting in britain completely safe. This is why I picked epirus ;)