Guess I'll change that next time around, didn't think the AI wouldn't be able to respond as well.
I must clarify I think 120 pop is a lot of fun and I don't think it shows the NR as OP since the IR and Warlords get battle-cruisers and SSDs that they can field in force.
I've also had very epic battle because the AI has done things I've not witnessed before on Admiral difficulty and that is making tons of massive fleets and essentially barricading me to one place. That being said the AI is still dumb in the fact it will attack me with a very small force unless I leave a large force at one of my border planets.