In 4x games number of turns is very important, especially from a conquest POV because:
1) you want to conquer the enemy before he conquers you
2) you want to build a stronger army faster than your opponent, otherwise you'll lose against a competent opponent
3) you want to research that advanced tech that gives you a bigger military advantages over your opponent first, or get crushed if he develops it first.
I'm a strategy game player and less a RPG'er so my answers are based on my own 4x strategy & wargame experience. "Timing" is always a critical factor in strategy games. Of course the AI is incredibly weak in this game so it doesn't matter too much, but if you plan on playing multiplayer you'd do better to move fast or you'll lose.
As far as level of victory points is determined in this game, I have no idea. Most strategy games reward you with more points the faster you can win, but typically give more points for other things (population size, # cities controlled, AIs vanquished, etc..)
