[Wids]

I believe it was the Star Wars: Rise of the Rebellion server that experimented with giving PCs height customization once. But, like Thayan said, the clothing/armor settings don't recognize the changes, so they ended up with tall characters with their enlarged heads hovering over their neck stumps, short characters with their shrunken heads inside their chests, stumpy little legs that didn't quite reach their pelvises (with certain Robe options), and such and such.

The idea was quickly scrapped, of course.

Simple body models come with their own troubles too. On the same server, Gamorrean characters use the same simple body model; you can dress your Gamorrean in head-to-toe Mandalorean Deathwatch armor and he'll still look like one of those leather-wearing, sandal-wearing guards in Jabba's palace. The simple model also causes problems when you try to mount a Gamorrean on an air bike; he looks like he's running the air bike along really fast, Flintstones style. So I imagine that using simple models with PCs would cause similar problems with riding horses, unfortunately.