-- I think Tim nailed it there. Moves like making the Library file hidden are there for the growing user base of non-Power Users. Making that directory not easily accessible by default means people are less likely to break things if they don't know what they're doing.
If can be unhidden if you need it regularly, or you can get to it through the Finder Go To Folder menu. I found it puzzling that it was gone, initially, but I understand that the OS X audience is broadening and that we're going to see changes because of that. I think we're going to to have to go a very long way, however, before I see Windows or Linux as a better desktop or portable option.