I own all the Changeling books. Second Edition was the last edition. BUT for the reasoning of their basic looks, it goes with what they could merge from human dreams after being around humans for such a long time. It's why they start OUT with banality since they're still partially human and the Fae soul is stained with it. Sure, some do have unique characteristics and they do differ from ages of the Fae Mein.
As for Seeming, I think you have it crossed. The Seeming is what their mortal self looks like. Which can in deed, be vastly different then your Fae Mein. The Fae Mein is the "race" or the type of dream the being embodies over the time. And yes, regional areas DOES infact effect the Fae Mein. But, the general description of each Kith is in fact a race.
It was all because of the Shattering and such they were forced to take familiar shapes.
The "true" Fae as it was, was the Sidhe. As they're the last to cross over, they take more of the traditional routes of the Fae.
But, everyone is a Changeling, Partial Human, Part Fae. If they didn't have the "human" part in it. Their Fae Mein wouldn't be as general as it is.
That's the reason for their general looks. Due to what happened in the past, it forced them to take familiar shapes and over time, their Fae Souls begin to erode with the rise in banality, they resulted in adapting to shapes best suited for the "dream" they're based on.
So, the basis of General Appearance does stay and goes with each portion of the age of the Kithian's Fae Mein, but aside from the "general" looks, the actual Fae Mein is unique depending upon each type of Kithian.
As for the Technocracy being "evil" They're not. Just, missunderstood. Just like the majority of all things from the oWoD.
Only thing sofar being truly evil is the Earthbound.
But, as things go on the Fae discussion. They didn't -start- out as Kithian. They were one. Then came humanity. Which fucked up rythm all along and -forced- them into shapes.
Now if they all had no general appearance portion on Kithian, they would always be truly immortal, they wouldn't age, there would be no Kithian and well, they would be a True Fae instead of a Changeling.
An example. All Satyrs have horns and goat's lower half. That's right. But forcing all Satyrs to be nude, or wear skimpy clothes in their Fae Mein is -bad-.
General Appearances need to stay. That's all I want.