I could do without a V12 so I don't care. I don't see why anybody needs a V12. Cadillac needs to concentrate on quality not V12 engines. When they're ready to take on Bentley or Maybach, they can start thinking about v12s. Until then, work on the V8s and get them at least as powerful (not supercharged) as Hyundai's V8.
If I recall correctly, the Sixteen will not make production. Though it certainly should.
Right now, GM was focussing on the DT7 sedan as a replacement for both the STS and DTS - but that's on hold for at least a year. The DT7, according to Motor Trend, will be Caddy's new flagship, doing battle with Lexus LS/BMW 7-Series/Mercedes S-Class. Which is a good thing, Cadillac seriously needs a flagship to compete with that price segment.
With luck, they'll bump up the price of the CTS a bit to be more in line with the 5-series/E-class, and introduce the upcoming Alpha family to compete against 3-series/C-class, hopefully limiting the undercutting of the competitors' prices. It's OK to be seen as the value leader, but Cadillac has had serious troubles being seen as a credible threat to the Lexuses and BMWs of the world.
I've heard rumors that the Alpha will start at $25K. A $25,000 Caddy would be the kiss of death for Cadillac's credibility in the luxury segment, forever dooming them to the near-luxury game.
I was never a big fan of the Sixteen, myself. Apart from the grille and lamp units, it didn't really say "Cadillac" to me. I has some beautiful details (A 1000 HP V-16!) and a superb paint job, but overall it kinda' left me cold.