How about sarmatia? they gotta move real quick, with the vandals and huns already as a horde, and the lombardii and roxolani eager to fight you (well, al least thats how it has been on my VH/Vh campaign).

I have had some serious troubles trying to settle my people. At the very beggining i let the vandals and huns go. Unfortunately, the huns came back and tried to finish me in the bridge near vicus sarmatae. I destroyed 3 stacks of their army, but i lost about almost a full stack on my own.

Now we(the huns and myself) are struggling ofr the control of the former goths settlements. But now im being forced to face an army full of lombardi bersekers and the rox faction leader...

I cant really complain of the harde missile troops, they do their job very well. But the infantry, on the other side, is absolutely terrible. Basically, the enemy can always count of routing them the very same second they carge them. I just cant trust them to do anything. Right now i dont know if im gonna make it on this campaign... but at least i have learned some lessons about being a horde...

Anyway, campaigns in BI are most definately way harder than RTW, and even MTW(i tell you, Expert/Expert early turks were easier than this), and that can only be a good thing.