I am not a developer, but I will comment on your suggestions for the standpoint of a calibre user.
They strike me as just too much. Calibre already suffers from trying to cover everything. The user interface is not always, for new users particularly, easy to understand. This is caused by the cross platform nature of Calibre, to some degree, but it is also caused by the many many operations calibre can already perform.
To add all this additional functionality is like to create an impossibly complex piece of software. Calibre can be tricked into doing some of what you want. But you also want to add player technology in 3 operating systems. Kovid is one person who is helped along by others. The nightmare of trying to maintain the complex software you propose would be a headache for an organization of Microsoft's size.
Since the software is open source, it might be better to suggest a different project for others starting with some of Kovid's code base and re-aim it to accomplish to ends you are seeking. It might be possible to refer to the calibre database, once redesigned for network use, to accomplish what you want to do.
As a user, I don't want calibre to become any more complicated to address issues that don't pertain to me at all.