Well, if the game reaches too large of an audience I will definitely lose all interest.
Nothing good ever comes from large masses of people. BUt I wouldnt worry about that.
You see, I cannot deny Sid or Fireaxis the attempt to bring in the Average Joe into the Civ flock even if it means I'll leave.
But I think its a futile attempt, the Average Joe spends his days updating facebook, toiling at work, doing some virtual farming, few sport games/TV shows, etc. He will not spend his hard earned $50 on Civ5, so what they'll end up with is losing mine and his $50 alike and declaring the franchise dead. The strategy (real strategy for using brains, not the tactical simulations called RTS) market is a niche market, IT WAS ALWAYS a niche market. The size of Civ community is already staggeringly large for that genre, anyone who likes strategy liked at least one Civ game if not more. There is more then enough money here to finance a quality game without reaching for the lower half of bell's curve.