Expeditions: Rome - Death or Glory Review (Molotova)
Short version:
I would recommended for a fresh playthrough for the arenas, not so much the new class.
Longer version:
The DLC adds a new class, the gladiator, and arenas in each of the 3 open regions (not the Rome Colosseum though!)
The Gladiator class is a bit underwhelming. Its main mechanic is "retaliation", counter-attacking melee attacks, but, on higher difficulty levels at least, if the enemy melee attacks are not absorbed by Praetorian shields you're probably doing something wrong.
The arena fights are great fun, if you're enjoying the tactical fights in this game... (if you're not then the whole game, not just the DLC is not really for you.). With one exception I am aware of they have no impact on the stories and quests of the main game.