That being said, I'm pretty sure that's not taking bound spirits into account? Shenhua's got her absurd wardrobe of object spirits plus maybe a fallen star spirit, Yuan He's got his dragon, Jiao's got Xin, Linqin has the dress Shenhua made her, etc. The higher up you go the less common peer level spirits to bind are, but most of the big shots we know have one to back them up. I'm not sure how exactly the math changes there, but I'm pretty sure it does still change.
Yrsillar's statement was also an average, and there's at least one guy we know, Elder Zhou, who made a career out of killing Khans all the way up to being peer level with him despite not having a bound spirit as far as we know. I wouldn't want to bet on a random Cloud Tribe Violet over Xia Ren, even if I'd expect one to come out on top against the average Imperial Violet.
I'd also note Cloud tribe cultivators advance by hunting worthy opponents(which is why they are having a hard time after having culled the upper range of the ecosystem for millennia). Basically all of them are some variety of Warrior Cultivator, while imperials are spread wider.
So Cloud Khans vs imperials Sovereigns:
Cloud
-Higher raw potency and thus bigger resource pool due to twin souled. Triple souled if they had a star bond.
-They got there via very lethal fights with peers. Of the Imperials this is much rarer, though they exist(see Sun Shao). Combat oriented Ways matter significantly in a fight.
-Mobility advantage, they've been flying since Red(with props), they are just going to be better at 3d combat.
-Action Economy. While an imperial cultivator Could have peer spirit partners making up for the twin/triple soul, the imperial method would generally have the spirit lagging somewhat behind in raw cultivation, as the areas of responsibility needed to grow are largely spoken for in thr Empire.
Imperial
-Better equipment. A Cloud Khan's equipment supply diminishes dramatically as they advance, and would be more along the lines of leveraging high quality materials inherent qualities. Imperial crafter sovereigns are numerous enough that its quite reasonable to expect to be able to commission a full kit of whatever high end gear you need eventually, though it won't be cheap. Added to this Imperial formationcraft is worldclass.
-Better arts. Owing to the jade slips being invented in antiquity, imperials are far better at preserving and iterating on their arts, with considerable references and theory when you need to innovate. Cloud tribes basically have to do master-apprentice, which limits this.
-Numbers. Even the ES, as depleted as it had been by the Hui's mismanagement and the civil war, has more high cultivators than the cloud tribes combined. If they are 1.75x as strong we have thrice as many, even if only one out of three is a dedicated fighter.
