Work faster gerdammit!!!!11!
I'm kidding, take as much time as possible. I think once Iron Europe comes out it'll be the NW mod that doesn't die out.
Depends when it gets released and how it's going to be advertised.
If people and regiments are just going to treat it like a "extra" think outside the NW events, then yes it will die out quicker.
But if regiments start to replace NW, N&S etc with Iron Europe, then we will see a longer life spand for the mod. It all comes down to how the IE team decides to advertise it and if they get big permanent regiments to support them and back them up (77y, 33rd, 15th etc).