I'm curious, would something like the Blizzard Authenticator key be a way to protect things?
I sense most people don't mind logging in at the start of a session so much, it's the rudeness of expecting to be able watch our every move while we play that irks people.
Personally however I think Steam has done the most to defeat piracy, and while it won't go away, all the time I can buy games simply, conveniently, and know they'll work, update and patch themselves and not cause me any hassle, I'll keep buying from Steam, especially when older games are so cheap it's hardly worth googling the game title with the word 'torrent'.
I also use GOG and D2drive, I just happen to prefer the steam setup.
Most people seem to be on the side of make the games attractive to genuine customers however, and DRM pushes against that, treating the customer like a criminal, and the criminal like a valued customer 'here's our game, with all the DRM stripped out, enjoy!'.
DLC, bonus content mailed out to genuine customers, anything like this can help.