That I can concur with. Expansion is the key to power in SEIV, as nothing can save you if you do not have enough colonies at your disposal. But then, my views may be a bit biased by my own focus on economics (you won't see me giving much interest to the military).
Speaking of which, I should brace myself to stand against the next player to reach my level of the hill. Last time I had the Steamroller, so it cannot get worse, can it? Oh, and good luck against the Usurper Primitive. I am putting my marbles on you as usual.