I voted that they are less optimal than the vanilla ones. The reasons are simple:
1. Vanilla bombers have Laser Guided Missiles.
2. Vanilla bombers have Air to Air capability.
3. Vanilla bombers guns are as effective as AF bombers, but there is a lot more infantry on vanilla maps, making the machine gun strafes a lot more effective.
4. Vanilla bombers have only to fear other planes (if the pilot is decent) because of their speed. AF bombers can be shot down with AA cannon fire alone and APCs will be able to track and shoot down an AF bomber as well.
Now, why are then, all bombers in AF so effective?
1. There is no substantial Air to Air threat. No missiles will lock on you, so decent piloting will get you out of most Air combat situations. The difficulty of air to air combat in AF due to the lack of missiles makes for very meager rewards of shooting an enemy plane. The time it takes to track, follow and shoot down a decent pilot is enough to do a full bombing run and a reload in most cases. I will pursue air to air combat only on a plane that is already smoking. I have done full sets of games with no deaths as a bomber pilot in AF. There is very little risk involved if you limit your bombing runs to high altitude bombing. Although you are slow, most planes will take two missiles and still fly, so you are OK as long as you do maintain your top speed, and keep out of straight paths where AA cannons will be able to track you.
2. Because of the amount of vehicles, AF is a target rich environment. Most bombing runs are decided on the amount of probable targets alone. In Vanilla, your radar targets are scarcer.
3. The front guns are very good against light armored vehicles and infantry. Also, they rip little birds apart quite well if you have a good vector of approach. They can take other planes, BUT, you need a very very good first strafe or you might be in for a long air fight if you want to down your enemy.
4. Low speeds allow for very maneuverable aircraft. The Frogfoot, however, has a tendency not to be able to pull down from a steep climb, which is the only maneuverability issue I have found (pull up to do a loop if in this situation). Note that the low speed also allows for easier landings, which is the best way to fix an aircraft if you are good at landings. A-10 seems to be the best overall craft of all three, however there is a little thing about the Fatan that makes it my favorite (perhaps the map where it appears).