This feature exists in the software. But only people with administrator rights have permission to view deleted pages.
If you want to see a deleted page you can usually ask an admin. They will generally restore it somewhere where you can see it unless it was deleted for some privacy reason.
Well, that sucks, and demonstrates that this would be absolutely trivial to make work correctly. This feature (in the normal "not removed due to legality or privacy concerns" case) should not require an administrator any more than viewing the normal edit history of a page.
Yeah, I wasn't supporting the current policy... but it looks difficult to change it. Your proposal has come up from time to time, and it's been strongly opposed by the legal counsel for the Wikimedia Foundation, for legal reasons: "community adoption of such a disastrous policy would create an actual emergency that would likely require Board intervention" http://en.wikipedia.org/wiki/Wikipedia:Village_pump_(proposa...
If you want to see a deleted page you can usually ask an admin. They will generally restore it somewhere where you can see it unless it was deleted for some privacy reason.