In a 1v1 scenario:
vs Paragon: Paragon using Tachyon lances outranges Conquest because of Advanced Targetting Core, even if Conquest is using the Gauss Cannon build. Conquest gets outranged, outgunned and outsustained.
vs Onslaught: Onslaught can easily catch up to Conquest using the Burn Drive ability. Conquest's Manuevering Jets aren't enough to maintain distance. Forced to a close range fight conquest has no chance of winning against Onslaught's superior everything.
A paragon is 60 DP to the Conquest's 40 DP, so I'd certainly hope that engagement would be in favor of the Paragon. In this case, the comparison should really be a Conquest + 20 DP of whatever vs Paragon, or 3 Conquests vs 2 Paragons.
vs Onslaught, yeah it's a bit of an uphill battle here. Much of the main advantages of maneuverability don't crop up very well when the Onslaught fights a Battleship like the Onslaught because of the Burn Drive. In this 1v1 scenario, the Onslaught benefits from its advantages but doesn't suffer from its disadvantages; Burn Drive is a system that makes it very easy to get into trouble but is also completely incapable of getting itself out of it. If the Onslaught meets opposition that it can't just overpower quickly, it's up a creek if it's being pursued by ships that are faster than it (which is all of them). Conquest's system allows for improved ability to fall back if the oncoming volume of fire is too high, though this advantage doesn't show itself very well in a theoretical 1v1 vs an Onslaught for obvious reasons.
Overall, a strict 1v1 comparison isn't particularly useful in this case, as you're (presumably) not actually fighting in 1v1 gladiator cage matches.
In a tactical scenario:
Conquest is sporting 4 large ballistic slots, but can never get to use more than 2 at once without getting in the middle of a fight - which it mustn't do due to it's weak armor and 90* shield with the worst flux/dmg ratio in the game. Resigned to a long-range support role it can never use more than half of it's weapon slots. An Onslaught would provide far more firepower and another body to tank the damage for the same Deployment Point cost while the Conquest is sitting 1000 miles away doing comparatively little.
The Onslaught's big gun arrays is deceiving, as it doesn't actually have the flux to operate them. The Onslaught's flux throttling issues essentially force the vast majority of the guns to be less effective flux-sipping versions, and even then it falters in sustained fights if more than one firing arc is active. Conquests on the other hand have far more flux and make great and sustainable fire-support platforms with advanced weapons like Mjolnirs. This doesn't even get into the utility of the 2 Large missile mounts that can be trained on either broadside.
In a strategic scenario:
I can't confirm this rn but I believe the conquest has a comparable or even higher price than the Onslaught. Also has the same maintenance of 40 supplies/mo. It has the same fuel consumption as a Paragon at 10 fuel/ly. It has 1 more maximum burn so there's at least that going for it.
Paragon is something of an anomaly as it has Battlecruiser-grade fuel consumption, despite being a Battleship. The Legion battlecarrier and Onslaught battleship both eat 15 fuel/LY, so I wouldn't be surprised if Tri-Tachyon's pet project eventually gets its logistical stats hammered to match accordingly.
Conquest's +1 maximum burn is a big boon. When using sustained burn (and an 8-burn fleet) while skill-less, that translates to a 14% increase in speed, which is also a 14% reduction in transit time. That 14% less time getting from Point A to Point B effectively means that you're spending less in-game time on your workload, and less time spent effectively means less supplies consumed, which means more money. Conquest makes for a much better exploration flagship than the low-tech Capital Warships for this reason, and it can blast Pirates, Pathers, Salvagers, and anything except perhaps red-level Remnant systems just fine.
The only better combat exploration cruiser is the Odyssey, due to good cargo and fuel capacity on top of an amazing 8 fuel/LY and High-resolution sensors. Of course, the main problem with acquiring an Odyssey is
finding an Odyssey, so you'll probably be stuck with a Conquest as your best bet, anyways.
All in all there seems to be no reason to buy a Conquest over Paragon/Onslaught right now.
I'm curious, let's flip this on its head. Let's say you're right and the Conquest is bad. What changes, specifically, would
you make to the Conquest that would make it be a worthwhile option in your opinion? (Specific numbers would be preferred, if possible)