Didn't claim anything to the contrary.
Simply said that Rome being weaker than they are now in vanilla is against historical accuracy. But I know it is a moot point, you must nerf them for gameplay reasons, as you have stated, I understand that.
Although, you could do what SPQR: Total War did and buff them, make them as strong as they truly were, and balance this out by making Carthage incredibly powerful, enough to crush all of Romes armies in the first two turns. That way the start of the campaign is hard but after that Rome will only get stronger, while others decline. Some would argue that is boring, I'd say it's an interesting approach as you have to struggle to gain power...