I sympathize with the OPs point, and I appreciate the overall discussion and counterpoints.
Back in the 80’s when there was much less info available, the Orlanthi felt like clear underdogs and the the Lunar Empire was a fascinating and ascendant anatagonist. If your starting point is after the Dragonrise and you have access to KOS and the Guide, it can look very different, and it makes it harder to cheer for the Orlanthi when you know they are going to win. I understand why KOS had to be written and the game setting updated, but c. 1612 seems like a better campaign setting to me, and even more so without the foreknowledge of Lunar defeat. If it feels like the Orlanthi are on their last legs and facing complete defeat or extermination, the stakes are higher than if they have just turned the tide and are going to win and win and win (granted it’s more complicated than that, and granted people have started their campaigns earlier and played through the great winter, for example. But the vibe is that the Lunars are going to be a bit of a punching bag when you start in 1625) Having said that I absolutely love the new edition, and the huge amount of material available in the Guide. The fact that some of the information is going to overdetermine the future or force you to Vary your Glorantha more from the official timeline if you don’t like it is inevitable.
I don’t necessarily feel so sad for the Pelorians - I think of them more like Egypt - not a massively expansionist empire, but an incredibly enduring one, and that is awe inspiring in a different way. It’s the heroes and super heroes that rub me a bit the wrong way. They are super interesting and iconic figures, but to me Argrath and especially Harrek seem to be missing tragic flaws. They are not just inevitable but no one can stand up to them. Yes Argrath faces setbacks but he is ultimately unstoppable unlike say Alexander the Great or Achilies. And it seems like absolutely nothing can stand up to Harrek and I wonder why he isn’t just ruler of the world (I’m not clear on when or if his end comes - if I knew what ultimately caused his end and their was something dramatic or noble about it this would change my perception. But as it is he feels undefeated since age 11 or something). Kallyr and even Jar-Eel seem more human to me and therefore a bit more interesting and sympathetic (yes, Jar-Eel is the most godlike, but the fact that she forfeits a battle because she is horny is a very interesting flaw, and the fact that she is killed by the unstoppable Harrek makes her more flawed or maybe just more sympathetic than the two victors. I also wish that there was a triumphant feminine hero instead of them always losing to boys. Having said that, I do like that Argrath and Harrek are not portrayed as “good” and that there is room to portray them as powerful villains, and that there is room for a multitude of viewpoints is why Glorantha so compelling to me. The history is definitely rich and complex enough that I do think the Pelorians can justifiably be proud of a glorious legacy even if their culture hasn’t spread as much (isn’t as diffuse?) as the Orlanthi Culture.