Well of course, why else play if not to have fun? But for me it would be more fun if I could actually win the game and declare war on whom I chose.
I think if you play through you will find that 150 turns is more than enough time. You are starting in the Industrial/Modern era with the world already made and cities already largely developed... so that's plenty of time.
The first game I am playing just through the industrial era, just to give it that WW2 feel. Of course I can't build atomic weapons, but oh well. I will let you know what I think of the scenario as I go along.