I think its a little boring, that the vehicles and boat are so slowly, that you can hardly use them to anything. It takes like Hours to drive from one city to another, who wants to just sit and wait that long, too get shot by a plane, in about 2 secs.
The ships are also to slow, and you i dont think you can use them to anything, useful other than, if you just like to sail around, and do nothing. I have tried to use the boat in combat ONE time, but normally the planes are flying in 5 ft or more, and you cant shoot at them.
I think it would be more fun, if the two other types of weapon (vehicles and boat), could be used for something good.
Well thats my appinion