A few points:
The 7 is no better. The 7 series borders on bland with a few bits of odd quirks thrown in (the huge grill that doesn't have any relationship to the headlights...it looks like it was just thrown on there, and the Korean style tail lights).
The A8, well I haven't seen it so I can't judge.
The LS is handsome enough but it's not bold, or beautiful.
The S is handsome besides the Maybach rear end...even after all this time I still don't like it. I wouldn't call it beautiful.
The XF...I liked it when it first came out but I'm already bored with it, whereas I still find the XK beautiful.
Now, I agree completely that the Sixteen could use an update, in fact with all this talk I may try my hand at a chop. However, I feel you're being overly critical of it, especially when you look at the competition listed. On the other hand, I've always felt the would slot up more towards Phantom/Arnage/Maybach territory. Of those three, 2 are more than dated, "timeless" if you will. The Interior of the Phantom is very blocky and dated looking. The Maybach looks like an bigger, fatter, uglier S-Class.
I don't feel that the Sixteen as horribly dated, I just feel it's showing it's age a bit, and that's only because of Cadillac's recent concepts and the CTS, not because of the competition. I feel that with a front end more like the CTS would cure my on real gripe with the car. The interior? It could be made to look more techy, but I do like the old-world look it has right now. So long as the features and quality are there I'd have no problem with it.
turbo, I'm not sure why we are butting heads lately but I just want to let you know it's nothing personal, we just happen to be disagreeing (while agreeing at the same time in this case) on styling lately.