Well, the Korx just beat me! Huge galaxy, tight clusters, everything common, masochistic, with the Drengin, Korath, Krynn and Terrans also playing, and me as Thalans. I resigned the game after they drove me back to Thala and a few barren worlds - at this point, they had 47 colonies to my 6, with the Terrans and Korath next with about 20 each. They were at war with me, the Drengin and the Krynn and beating us all. Out-expanded, out-researched and out-built everyone, with a strong economy, and conducted invasions well, conquering my best planets in fairly short order. Built Galactic Stock Exchange, Restaurant, Bazaar, Xinathium and the Mercenary Academy. In short, entirely unlike they have ever played before.

What went right? Well, I was stuck out on a limb (Thala and two other worlds literally half the galaxy from everything else) while they were sharing a big cluster with the Krynn and Korath, so I wasn't going to be much of an impediment, and they had the pathetic Drengin as a buffer between them and the Terrans. Friendship with the Korath seems to have helped, there was obviously a bit of tech trading between the two as some of my modded Korath research buildings were on their planets along with Devil's Forges, and they had traded for cut-throat trading too - but I should point out that they weren't relying on the Korath for military help, the Korx ships were slightly more advanced, using medium hulls while the Korath stuck to small. The one thing they weren't doing was building factories - in fact I'm not sure how they were churning so many ships out with such a small industrial base.

I was playing with my hybrid mod, based on MarvinKosh's & Tolmekian's and the commentary in the threads for those two mods, along with my own Drengin and Korath changes (of which the Korath have been far more effective). So the majority of tech tree issues have been fixed, but I can't imagine that alone made the difference otherwise you would have noticed it already in your games too.

I'm going to play through a game as the Drengin to see if I can work out what's making them suck so much, I'll throw the Korx into the mix and see how they do!

Switched to AI 8, which seems to do well with them. They were appalling on AI 7 - though even then not as bad as the Drengin - and I couldn't figure out how to fix it (I'm pretty new to modding).

I'm playtesting some Drath changes at the moment, trying to clean up their tech tree.

I'm not sure if it's part of the reason that they're bad, but it bugs the hell out of me that they get entertainment centres, temples and healing pools, none of which upgrade to each other, and which they seem to stuff their planets with rather than building factories and research buildings. I don't know if it's the AI trying to compensate for slow population growth by maxing out morale (which is not a bad strategy), but it means that their planets are full of wasted tiles with low-level buildings, and they end up falling behind on tech while also failing to expand.

The healing pools thing felt like a bodge anyway, so I deleted it from the tech tree entirely and added an improved temple with exactly the same attributes to Shrine of the Mithrilar (same thing for the Altarians). In its place after Divergent Evolution, I added a new tech (Ancestral Refuge) with a 1per planet morale/pop growth structure (with the justification of it being a recreation of their original evolutionary environment on Altaria, somewhere they can relax and do whatever 20-foot-tall shapeshifting space dragons do). This is quite an expensive structure so it won't help too much straight away, but should pay off later when they get to fighting wars.

To dissuade them from building Entertainment Centers and then failing to update them later, I simply deleted Industrial Revolution from the tree entirely - I'm playing with MarvinKosh's tech tree changes which eliminate the other early structures so there's no loss to doing this, and just shifted the social bonus on to Way of the Drath (did the same for the Altarians and moved bonus to History of Benevolence). I suppose an alternative to this would be just to set Temples to update Entertainment Centers, but I didn't think of that until afterwards.

The last addition was an "Adjustment Bureau" starting structure - a one-per-planet propaganda & social manipulation structure slightly buffing various stats including economics. I felt that it was in keeping with the Drath's background as manipulators and that it would help them cope with their small populations in the early game (in the late game, I'm hoping that the Bureau's small bonus to perceived might will help them, but I haven't been able to tell yet - this part is entirely experimental as to my knowledge the only perceived might structure is the Spin Control Center, and I'm still trying to figure out what value to give to a non-wonder version). The general idea is that it's a characteristically Drathian version of the Krynn structures, with a focus on staying out of wars and resisting cultural conquest rather than increasing planetary influence.

I'm on my second game against the modded Drath and it does seem to make a difference, though I did also have to go back and boost the AI value for Xeno Research and Xeno Industrial Theory between games as they researched a bunch of invasion techs before having manufacturing or research structures. But they seem to be colonizing and building more sensibly, and I'll feed back on my current game when it's done.

I've finally encountered some strong Drath - in fact, they and their friend the Krynn are likely to defeat me. They both declared war after I attacked a minor race version of the Drath (long story) and are out for blood - two peace attempts resulted in war being declared again on the next turn. Both of their standard ships are better then mine, and as soon as they get Planetary Invasion, I'll likely be in a lot of trouble.

I'm playing as the Drengin, against 9 AIs, with the three other evil races in to deal with historic problems I've had with everybody hating me when I'm evil, but it has done little good. The Yor and Korath are both friendly, but they're engaged in a three-way war with each other and the Arceans - who inexplicably declared war on most of the galaxy about six months ago - and are too far away to be any good. I'm pretty sure the Drath are keeping the war going, too. The only other race to like me is the Altarians, and that's probably just because the combined attack of the entire military is 3 points of beam - once they finally build up, I expect they'll hate me too.

However, while I have yet to make contact with them, by all appearances the Korx in this game are still utterly lame. One of my "all AI" test games does have strong Korx, though.

Just thought I would chime in here, I have encountered strong Drath on my relatively unmodded games before (relatively being kryos hull system mod, a anomaly, invasion and government booster, and a few custom tech trees, all of which should have no real effect on general AI performance)

One in particular had them as the dominant AI in the galaxy, this one was on a medium map and they had half the galaxy for awhile. In fact the Drath are generally in the top 5 races in nearly all my games.

I also have an odd issue with the Altarians ALWAYS spam-researching Planetary Invasion techs so far ahead of everyone else it makes my head spin. Korx, Arceans, and of course Drengin are my personal eternal underdogs, and I dont think that the Arceans speed penalty is the only thing holding them back.

They seem to be built as a galactic "turtle" race, to build up planet defenses on each of their planets till its invincible, conquer a few more, rinse and repeat until they can just steamroll the galaxy. They just seem to have poor resource management, not building their unique techs and pretty much standing back from everything. Doing nothing of note seems to be their general problem in my games.