I'm curious about what kind of player retention they have among the players who refuse to pay in at all - those players are important to keep those willing to pay, sticking around.
Wins the thread.
Lots of good ideas in this thread.
Personal opinion: WoW will gain players if Blizzard significantly lowers the sub or drops it altogether. The latter will certainly increase players and will be the death of private servers.
Blizzard will have to consider several things including:
1. Impact on customer service (so many tickets will be generated)
2. Impact on game servers (people will also create spam/alt accounts)
3. Impact on other blizzard games (people will move from Diablo to WoW and vice versa for example)