Given the range limited nature of EWM, assuming a player piloted energy Onslaught, I wonder if swapping the ITU out for something else would be worth while, like IPDAI (and maybe swap a skill for ePD?) or perhaps Auxilliary Thrusters.
In regards to Onslaught effectiveness and bringing weapons to bear, I find that Onslaughts essentially define the line of fighting, so they shouldn't need to turn all that much, especially against an opposing capital or cruiser line. When properly supported by frigates/destroyers they shouldn't need to change their attention to flankers, and in any case still have a high amount of firepower in their forward 240 degrees (can bring to bear at a minimum 1 large slot and 3 medium slots in that 240 degrees).
Also, as charge weapons, Thermal Pulse Cannons have their DPS much less affected by time off target than others, so being in a hardpoint isn't as disadvantageous as for other weapons. A 20 Charge capacity (and 1 charge gained per second) at 5 shots per seconds runs dry in 5 seconds. It takes 20 seconds to fully charge after that, so they really only need to be on target for about 20% of the time to get a full DPS benefit. Also, depending on skills, can reach out to 1,750 range units (1000 * (1 + 0.6 + 0.15)), and are well placed at the very front of the ship. They certainly out range hard-flux Radiants. Not sure how Paragon beams hit 2500+. I thought vanilla max beam range on a Paragon was 1000 * (1 + 1 + 0.15) + 200 = 2350. In any case, TPCs also have a solidly long range with ITU.
Admittedly, I do tend to run Elite Impact Mitigation and throw on Auxillary Thrusters on Onslaughts when running them in the campaign to improve their turning ability.
To be honest, in a 6 vs 6 AI controlled Conquest vs Onslaught matchup, I'd put my money on the Onslaughts. Actually...
Just tested a simple AI battles (the PVP mission mod) with 6 conquest_Elite versus 6 onslaught_Elite variants, twice. The Onslaughts came out on top with only 2 ships lost, and then only 1 ship lost. Seems like the AI handles them just fine when compared to Conquests at least. Sure they're clumsy at moving around but they're just that strong. Also I have to mention, it is hilarious when an Onslaught clips a dead ship while burn driving, flames out at full speed, spins around slowly while firing the entire time at an enemy Conquest, flies through the Conquest line and ends up in a perfect flanking position on the other side... Anyways, one could obviously tune up the ships with much better tuned player designed setups, but at first blush there doesn't seem to be any issues with the AI handling.
Anyways, I'm open to fleet comparison suggestions or some objective comparisons of capital performance under AI control, but it's my experience in the latest release Onslaughts are quite good for the DP, both in human hands, and relatively in AI hands, when combined with skills.
