I voted yes mainly on the basis of the practicality arguments other people have already raised. ie if there is only a limited number of unit slots and EB wants to accurately represent 10 new factions then the team will need to prioritise.

Also, I would introduce another argument - and I seem to be the only one to consider it...

The game for me is not just about historical accuracy, otherwise we would play it every time with the Romans and Parthians winning. We chose to play other factions from time to time in order to play a game of "what if". So maybe in this alternative history another faction takes over the Mediterannean world and (as an aside) the Roman culture is extinct by 170 BC?

How did this faction manage to control their empire and deal with the social and military pressures that success would have had on their homelands? Almost certainly they would have had some "Marian" reforms of their own. To me EB cannot be about recreating history exactly and entirely, it is simply putting you into a specific position at a particular point in time and letting you create a new alternative history. As such I would personally prefer to see more attention given to other factions' reforms (even if based on speculation) before lavishing further attention on the Romans at a point when for all practical purposes they have already won the game.