Found this strategy quite powerful, especially for empires that are not focused on military side of tech tree you can acquire 6 foreign legions when everyone else has longswordsmen on Immortal difficulty. I just went for Industrialization ASAP as a commerce strategy, then rush bought 3 Factories and got the 2 free tenents, then one more policy unlock and BAM. You can have really advanced offensive army. I had to use Oxford university for it but I think it can be worth it if you decide to go to war against someone. I did this with Assyria and got some nice techs by capturing some babylonian cities . Can support the legions with some Gatlin guns, and ofc build the Big Ben too! Maybe it's a bit too powerful strategy to get powerful infantry way before anyone else. Does it need balancing?