> What would we lose?

You'd lose the ability to work on and distribute software not approved by your and various other governments. For example, if the UK makes BitTorrent illegal, what happens to you when you've attached your identity to your torrent client when you try to enter the UK (or already live there)?

Security must be solved without removing anonymity.

I love how people blame anonymity for the current internet problems. Whereas when anonymith was the default we had almost none of the problems. Most of the problems seemed to have started once anonymity stopped being the order of the data, and things like Facebook and Twitter became big where everyone's real identities became tied to their online behavior.