In "Yesterday's Enterprise" and "Rascals", two K'vorts defeated the Enterprise-D.
In STO, three standard BoPs will hardly scratch a Galaxy cruiser.
So I think the Raptor design - more durable and hard-hitting, but slower to turn - would work best. Especially since the K'vorts in canon weren't very maneuverable.
Problem is, a Raptor's basically 3/4 of a Cruiser based on handling and structure, has a very definite 'shape' that is NOT a Bird of Prey shape (in fact, LOOKS like 3/4 of a cruiser-skinnier but the same layout hull-to-nacelles), and like it or not, we have some visual cues on what ships are supposed to look like, and from that, how they're supposed to handle. The KDF is SWIMMING in Cruisers at this point, and swimming in cruiser-like vessels, the only vessels we really have (other than the Nausicaans) wiht any real turn-and-handling, have wings and a kind of canada-goose-meets-vulture shape...
That is a very, very, definite shape.
Even the Hose-us follows the Bird of Prey layout, in spite of looking like a refugee from a 1980's Zoids toyline (or Lego product).
which is NOT a raptor's layout. The Raptor has key design differences visually-a long hull, narrow for the majority of its length, two large nacelles at the rear, and a rear hull/connecting structure reminiscent of an inverted D-7 cruiser. The relationship between a Qin and a D-7/K'tinga/Tohrkat is visible and obvious.
In short, "Raptors don't got wings", a ship with wings should NOT be a Raptor, just like a ship with wings should NOT be a Cruiser.
The structural cues don't line up, the abilities shouldn't strain too far between ship design families-BoP are built to Manuever, they turn and they burn, they sacrifice mass and protection and armament to do so, Raptors are designed to be close support for Cruisers, their turn rates, turn pivot point, armament, hull design etc. flow from a role as close support for a Cruiser (i.e. actually acting like they are "ESCORTING" the cruiser, as opposed to being named 'escort' because of size alone).
The inability to out-turn their main competitors (or even keep up, degrees of turn aside) in the same mass class on the other side, is a reflection of design and tactical doctrine-Raptors have better turn than Cruisers because of their size, whereas Fedscorts and Nausi destroyers have high turn because they are intended for a different role-one the KDF fills mostly through the versatile Bird of Prey-fast moving, manueverable ambush killers.
The BoP is the main reason there are so few (only one so far-and it's from 400 years in the future) dedicated SCI ships-Klingon doctrine puts Sci powers as part of teh fast-attack class, rather than Fed doctrine where Science/EW/Recon is a separate, dedicated ship classification.
The K'Vort is a big, or massive, or just bulky, Bird of Prey, it's derivative shape based on tactical doctrines evident in the rest of the KDF navy, is a heavy recon ship with enhanced strike capability, not a dedicated line-fleet ship designed to escort Cruisers in the Wall of a set-piece battle.
Given the additional mass (or bulk) evident in it visually, the K'Vort probably, based on doctrine, would have a slight disadvantage in turn rate compared to a Hegh'ta, but it would still turn faster than a typical Raptor of the same class/weight, it will maybe have a harder punch or more raw energy output than a Heggie, but functionally it is likely to be very similar, with only a slight edge in hull structure and/or shielding. Probably will have more power available to Aux and a slight increase in crew, but it won't, and shouldn't, act like a Qin-with-a-battlecloak.
Since the Hose-Us has four tac consoles, and this is supposed to be a different class of BoP, I suggest four of either engineering, or Sci instead, with the BoFF layout of a Fleet Norgh Retrofit, maybe 1000 more points of hull over the Hegh'ta, and a drop of two degrees turn. (from a base model Hegh'ta, which would be the easiest start point for coding, that would mean a drop to the 18 degrees/second range from 20).
The advantage is that this would be MUCH easier to code for the Devs, would fit the slightly larger appearance and 'beefier' body, provide a unique and different experience from driving the Hoh'sus or Hegh'ta, and still retain the fundamental character of the class as a whole-thus preserving the differences between Cruiser, BoP, and Raptor for the tactile senses of the players.
AND it would preserve the diffference in KDF design philosophy vs. Federation, Nausicaan, Gorn, etc.
One of the things I have noticed, is a kind of gripping desire for Tanky birds, which the BoP as a whole just isn't-and was never meant to be- on the forums here. Lots of love for Raptors and Cruisers, and what strikes me is a certain disregard for the fundamental graces of the BoP class and it's worthiness to get a REAL upgraded, genuinely T5 quality, example into the stores/shipyards.
The Bird of Prey class as a whole are "Swiss army ships" (well, with two exceptions-the B'rel really only excels as a torpedo boat and the Hoh'sus is, in all but name, functionally a copy of FedScort design philosophy with a Battlecloak installed, which may explain the exremental visual 'design' work...), they are "Raiders" in the true "Roger's Raiders" or "Marine Raiders" concept-go deep behind enemy lines, conduct a broad/wide array of missions that include every sort of combat mission one might need a ship to do-from penetration to deep strike, from VIP transport to Prisoner rescue, Kidnapping, assassination, mine-laying, mine-clearance, intelligence gathering, signals intercept, sabotage, rescue, insertion and extraction, and, yes, even a bit of Line fighting.
IOW they do missions that the Federation would have to send three times the crew, often on three times the investment in ships, to do, at higher risk than a Bird of Prey runs both financially, and strategically with smaller crews, fewer resources, and less external support infrastructure.
IN GAME what this means is, unless you're good at Lockbox lottery (or have several tens of milloins of EC falling out your ass), if you're a Science captain, and You are KDF, you get your best use of your abilities in (drumroll)...
A Bird of Prey.
Meanwhile, a Tac captain in a BoP can be DEADLY in PvP-even against opposition that can stack MORE consoles, more weapons, thicker hull and better shields, because a BoP, unlike a Raptor is a 'Pilot's ship'-means it's got handling and speed, you can actually manuever with it, evasive actually evades **** coming at you, and the flexible consoles means you can buff where you need to (or want to) depending on mission requirements-unlike ships with fixed consoles, where you're basically relying on someone ELSE to decide what you need and how much you get of it.