Hi Nicolas,
sorry for your tea!
The reference 5100 had a specific calibre, but was limited at 3000 pieces if I remember well, so not a small series. That was probably enough to develop and justify a specific calibre (that was eventually possibly partially re-used for the square tourbillon). I doubt that they will make that many celestial watches, but who knows?
Regarding going for a better finish of the same calibre, yes that's an idea that appealed me quite often, but again that's not something Swiss watchmakers do, with very rare exceptions. Yes they could have made one exception here, but they did not! The question is: is it hard to sell as it is? 
Best
Dje



