Alex needs to give the XIV Onslaught and Dominator heavy ballistic integration of whatever that hullmod name (the one that reduces OP price of large ballistic weapons).
It is sad to see the most effective onslaught build still being 90% point defense
I'm confused by this statement given Onslaughts did gain Ballistics Integration in 0.95.1a. Just double checked in game, my Onslaught XIV has ballistics integration.
Dominators didn't get the hullmod, but they did get a 10 OP bump from 0.95.1a, which is kinda like half the bonus (2 large mounts with the hullmod would be a 20 OP savings). I don't think I've ever downgraded the large mounts on Dominators I run, given they both focus forward and large ballistics tend to be the best ballistics. I don't remember seeing builds posted to the forums with people filling them with mediums, although perhaps I've missed it.
As for going heavy on point defense, they kind of are over mounted for their DP. If they actually had the flux to fire all offensive weaponry, they'd outgun Radiants and Paragons. Assuming 1 large = 2 mediums = 4 smalls:
Onslaughts come with 5 large gun mounts, 9 medium guns, 6 small guns, and 4 medium missile mounts (52 small equivalent).
Radiants only come with 5 large mounts, 4 mediums, and 10 smalls (38 small equivalent).
Paragons have 4 large, 6 mediums, 9 smalls, and 4 small missile mounts (41 small equivalent).
They simply don't need all their mounts dedicated to offense to put out good damage numbers, so filling the rest with PD to prevent Reapers from removing their heavy armor defense seems like a good investment.
OP's pic kinda confused me because I didn't see the hullmod in his pic. I haven't used Onslaught recently so I missed that
As about Dominator, even with the +10 OP still can't afford anything above Mark IX because of the flux cost Large weapons require a lot of flux dissipation and dominator doesn't have that. But that pilot skill that gives more flux stats for every op spent on weapons fixes that.
As about weapons, unlike the rest of the ships you mentioned, Onslaught can fire at max 3 large weapons at the same time at one target (a large one, 2 at small one)
But that's not the issue here, Onslaught simply can't perform well when more than 2 large weapons are firing at the same time due to bad flux stats. You can even see in the video posted by OP, if that was the AI it would have been dead. So this is why despite having 5 large slots, putting offense weapon in each slot feels like a noob bait simply because the price weapons (before the heavy ballistics integration) prevented the player from putting a lot of points in flux stats/hullmods