How long are you spending in Tunisia and are you planning on travelling outside Tunis? I believe Tunisia is now re-awakening quite quickly on the tourism front.
Some of us are awake long before others .
Trip report from a trip in about 2013: Tunisia - Carthage, Romans and Vandals (and Doha to start).
We're just spending five nights/four full days there - should be enough to see the town and nearby Carthiginian ruins (what's left of them after the Romans destroyed Carthage).
Two days is plenty for Tunis - try to get out of town per the Trip Report. (As you indicate, the Carthaginian ruins are in fact mainly Roman Ruins, with Carthage mostly just a squashed layer underneath )