I recall adding some custom code to make it play nice with the range-and-firepower-boosting ship system, though, so it doesn't (often) turn away from a target while it's turned on, etc.
Perhaps this piece of code could be shared to other capitals too.
The general idea is, less turn angle/rate per second then ship should tend to finish current target rather than make a defensive move.
Current situation with Onslaught, Paragon, Dominator, ... is they tend to switch to other target too quickly and start to turn. It looks like they prioritise the closest ship as target regardless of status of the current target.
Result is, the slow turning ships shoot at enemy get shields down, start to work on armour, then priority of closest ships comes in game, so now the AI cancel current target then acquire another one, then start to turn (lowered DPS ) then start to shoot at full shield of other ship. (no real dmg)
Better should be, a logic which evaluates danger of closer ship vs current target status (time to live - quick simulation/aproximation how long it would take to kill the target.).
Then result is, every ship evaluates his turning speed (defensive move) against advantage of finishing current target. It is ridiculous when frigates and Destro encircle Onslaught, then the massive ship turn self into a whirlwind to deliver few shots to each enemy but kill none.
Anyway, this logic might take some time to do properly. I would rather see a new update as it is now. :-]
One update per year is not much to ask, right?