I think RobO figured it out. I vote for that solution.
Dingocat, no need to pick apart my post. And yes, those are changes I have made, I was just proposing a couple ideas. I thought the extra wonder was a great solution to getting more out of the limited ships we have. As far as WW2 ships being so much better than their predescessors, yes, they were better, but not overwhelmingly so, as many ships used in WW2 were built during or shortly after WW1.
And then there's the matter that they were essentially the same ship, just improved. A WW1 Battleship and a WW2 Battleship were both Battleships. Obviously, naming is an issue. Something like a small wonder to improve late-industrial ships over earlier ones, without requiring more ships with more names, is not a bad idea.
I give ships blitz because they were pathetically ineffective to begin with. I wanted a Battleship within bombardment range to be a major worry, and blitz is a great way to do that. Of course, five or six attacks (or whatever your movement is) in one turn is way too much, so I gave them two moves with "all terrain as roads" tagged. Destroyers I gave three. I assure you, this makes naval combat much more interesting. Your reasoning of naval battles being long and drawn out seems odd to me, since one turn is equal to a year in modern times. You could get off a lot of salvos in a year.
I gave blitz to artillery units from the cannon up, and each have two moves. After all, artillery is the king of the battlefield, and only using cavalry charges as your main offense is absurd. My battles of infantry and artillery seem much more realistic than hordes of cavalry, with no artillery support, beating entrenched foot soldiers. Beyond that, I gave it to all air units, and in my "all foot units have movement 2" games, I gave it to Marines.
Elephants can blitz too. Don't really have any reasoning for it I guess.