For the Suebi I think they can make a good civilization.
The Alaman didn’t move from Germany and were rapidly conquered by the Franks.
Last November I made a post for the future of Roman civilization and a Barbarian invasions DLC proposal
I think a DLC featuring 3 civilizations (Vandal, Suebi, Roman) and 4 campaigns (Vandal, Suebi, Clovis (Frank) and Aegidius (Roman, already exist on the workshop) will be good to relate the fall of the Western Roman Empire because there all that still lack : Roman campaign, Frank campaign (featuring a lot of Axe thrower). Vandal need more than a scenario in Victors and vanquished and the Suebi traveled much.
The other barbarian kingdoms didn’t make conquest (old Burgundian and Alaman) and the late barbarian kingdoms are better to use in a Charlemagne DLC (Langobard and Saxon).
I think it’s good to put the romain civilization in this barbarian invasion DLC because after the release of Chronicles the future of Return of Rome is beyond hope. I enjoyed to play this campaigns but less than AoE2 and Chronicles campaigns. The best I enjoyed in Return of Rome is … playing against the Romans in the Attila and Alaric campaign ! It’s good tho give an option this buy the Roman civilization without have to buy Return of Rome in which the AoE1 content interest not much people.
Also I want a counter to the fire galley who don’t explode.