The idea of the Central Library is to be part driven, the symbol needs pin names but not numbers, they're assigned via the packaging process, so you can share common symbols (only need one instance of the symbol). We're working on this in the translators but not before VX.2. VX.1.2 will have further improvements to the translation process over and above what we did for VX.1.1.
As I mentioned in another post, the current central library structure isn't quite right but in essence it should (eventually) work in such a way as you require, symbols being graphics only (with pin names) and packaging information held in the Part information - it is exactly how it works in the Xpedition flow.