The problem with the Julii is that a lot of the Gaulish provinces are good only for manpower with huge unit size. And they have to be garrisoned against Germans and Britons. I think that Londinium is probably the best province in that region. But it is hardly enough. That is why I will always try to take one or two cities the other Roman factions normally take. I might take Carthage or perhaps Sparta. Normally I like the Scipii. I take the African provinces and move my capital to Carthage. Sometimes I take a Greek city for the money. I tend accumulate units and attack Egypt through Siwa and try to land an army in Alexandria. I try to conquer its cities before they reach huge size and therefore become something of a pain. I really cannot abide that Brutii green.