[lch]

Problem is, will this mean that it's a branch of the game? People who don't have that extra pack won't be able to play (extra) games with those people, right? So it's a mandatory update, for practical reasons? Will there have to be separate patches for the normal main game and the extra version? How do you want to do the serial number authentication on the web site? Look at Illwinter's homepage for a comparison of how much care goes into the web sites.

I think your idea is never going to get realized just because there's way too much work involved with not too big a payoff.