I've tried to 'correct' some of the things I found that held the AI back. Mainly the supply 'thing' (ministers sending the fleets back for re-supply waaayy to much) and AI's colonizing planets halfway accross the galaxy when there is a good one right next door. Engine mounts greatly reduce the 'refuel' time of the AI's and the Colonize all makes things rather interesting off the bat. One of the most valuable things I've found are sattellites, throw 200 on a warp point and nothing is getting thru except a fleet of dreadnoughts with barrier mounted shields.
Missiles are great, I love the Short Range Missiles and the X-ternal racks that can mean all the difference in a battle.
Further down the line I'm going to add mines that do varied damage types (engine only etc) and AI's that use them exclusively as well as an AI that uses drones as 'missile pods' (take a drone , add 1 or 2 engines and pack it full of missile launchers or a drone with tonnes of XT missile racks and a nice heavy warhead for ramming
)