It is only a surprise one time if the fleet all moved to sz 64 on the same turn that the Naval Base is built. It could be interesting at the right moment in the right kind of game. The Germans can not move troops from France to Russia as fast as the US can move thru the canal.
Maybe a a global game in which Japan needs the Hawaiian Islands to win and the Germans can not take Moscow.
I have faked builds on on side of the board and moved to the other in order to throw off Axis builds in other AA games. Especially when I knew I needed two rounds to be organized.