Riptide and Whacker,
Maybe something went fubar during DBW install? I'm on DBW 1.71 as well, and don't really notice the issues you're describing. The AI will make good use of it's energy, and will use energy tactics against you if it has an E advantage, but I don't see it creating energy out of nothing. Try testing in qmb, on Okinawa map with F6F vs Zero. You will start on his six about 1.5k behind him. On all AI difficulty settings, he should break left and try and cut underneath you. If you follow him, it should be pretty easy to get into a turn fight with him. On rookie, his turns will be lazy and shooting him shouldn't be hard. On ace, he'll fly to the fullest extent of his ride and will mess you up if you do it wrong. Now try the same setup, but vs a BF-109. Rather than breaking and coming underneath you, he should break the opposite direction and pull away from you in an attempt to create an energy advantage and set up a boom and zoom. He will be successful too, since the 109 is the faster plane. With equally matched planes, I see the AI doing things like pulling away only if he already has an energy advantage, which he will create if you're not watching carefully.
Dunno if any of this helps, just my $0.02.