[Squirrelloid]

Blitzes encourage people to be more aggressive, making fast research more in-line with the style of play in general. You'll fight your first war sooner, and at 12.5 provinces/player (with 4 people) you're likely to run out of room faster than you would be accustomed to in a standard game. Especially when some provinces are often water (and thus basically inaccessible to everyone since blitzing with a water nation just doesn't work very well).

So not only does the map size encourage faster play, but there is heightened aggression due to the necessarily short duration of the game, and arguably the low number of people rewards early aggression more. (Winning quickly is possible - there aren't too many people that you can't just steamroll them all).