We've never found the Aurea discounted drinks package price either...it may be something that either your TA or MSC would be able to add over the phone rather than online.
We have sailed both Aurea and Fantastica with MSC. Cabin placement seems to be hit and miss, some of the Aurea locations suck and some of the Fantastica locations should be more expensive!
My advice would be to book based on location or based on your need for Anytime Dining, the private sundeck access and having a Spa facilities pass which are the main draws to the Aurea package.
If you aren't going to use them, or think they are worth 1500 more to you then I think you'd be better off with a Fantastica Balcony.