Not that I know of. If I have to do this, then please see the "additional software" part of my post.

It's a free install. They don't include it as part of the operating system so they can upgrade it on an independent cycle. iBooks is one of the "Ten Apps that every iPad User should have" I'd also recommend GoodReader - which should be on every iPad (Except the US Air Force, who got worried it was written by a Russian)

It doesn't make sense to argue about this, since different users expect different things from their computers.

Either you think that users should be able to save any files they want to their devices (and move them to other devices), or you don't.

Personally, I wouldn't accept this even if iBooks was preinstalled. There are so many other file types that you just cannot move/save.

I would assume 99% of users install iBooks on their iPad. It's not that hard to download it.