So, Can you change the appearance of you character?
I know, for most of you this may not even matter at all,
but the lack of customization in the looks of these presets just totally put me off.
Or, maybe it's there, I just missed it?

No, not in-game. The character models are fixed in vanilla version.

There are a few character re-skin mods, but most download links are dead by now. Just google for the character you'd like to reskin and you might be lucky to find a working one.

E.g. Radiant Jen Zi Reskin
http://www.lucasforums.com/showpost.php?p=2335125&postcount=82
http://www.moddb.com/games/jade-empire/addons/sexy-radiant-jen-zi

Or you can swap the players appearance with that of an NPC character:
http://jadeempire-modding.wikia.com/wiki/Play_as_an_NPC

If you want to get into modding yourself, here are two links to start:
http://jadeempire-modding.wikia.com/wiki/Basic_Retexturing
http://www.lucasforums.com/showthread.php?t=177647

There are six presets. Three men and three women. Regardless of which one you choose, you will be unable to alter that character's visual appearance in any way. That includes facial features, hair or clothing options. But each model is visually distinct.

The only difference is gender. Different romance options exist for men and women, and characters will refer to your character by his or her proper gender.

All things considered, the almost complete lack of character customization should not turn you off entirely. That being said, if you are looking for a deep statistical RPG system with a lot of options for building your character, you won't find it in Jade Empire.