Ive followed the evolution of the STS pretty closely, and have never seen solid info about the interior, ALOT of hoping for a better interior seems to have lead to rumor becoming fact. I hope Im wrong, if you got info share it please..........
I don't know why everyone hates the CTS interior so much. I find it to be fresh and original, and unlike most cars, it complements the exterior styling. I think you will see it influence Caddy interior design for some time to come.
You are correct, there are many people who like the CTS/SRX interior. It was designed to be polarizing, like the exterior styling. The did tweak the interior slightly for '04. There was a new dark interior color, the gages were changed from amber background to white and the clock on the left of the tach was replaced by a temp gage.
The STS interior styling really dosen't carry over anything from the CTS/SRX except the shifter from the SRX. Much less angular with softer corners and higher quality wood trim. There is also a possibity of a brushed aluminum style trim in and around the center stack.