[Rich04]

Simplest solution. Defender always goes first. Often a smaller empires only defense is to guard a warp point so as to get that first volley off. It forces the attacker to attack with a larger force. In real life the defender almost always has the advantage. In fleet engagements away from warpoints it doesnt matter much since you have no way of knowing which side will close range first and open fire. (I have simmed this [who will fire first] many times with equal forces. The side that fires first has the advantage but it could be either force that is fighting.)

Harder solution. All ships target/fire after both sides move and all damage happens at the end of the combat round.

The only problem with init that I see. Is it will tend to help the player thats ahead anyway most of the time. If he has got the ships/fleets he most likely will have the tech.