I have very mixed views on the whole Mode S debate. For starters I do believe that it will improve safety and situational awareness using the weather uplink services and traffic information. I have a GNS430 and in my aircraft that is capable of receiving traffic and weather data via the Garmin 330 Mode S unit. For my Instrument flying this is a positive benefit.
I don't think that there is any implication on the civil liberties and the right to fly unseen. What it comes down to at the end of the day is money. Pure and simply most people can not afford the current cost of the mode S equipment. These are people that are flying old aircraft with neither the space and often the electrical system to drive them. Most people can't afford to fly and make great sacrifices to be able to get into the air. These are the people that mode S will hurt.
I have mode S about to be linked to my GNS430 and think the potential is huge for my type of flying. I experianced the benefits of Mode S equipment while instrument training in the USA and believe that the benefits outweigh the costs. But I also firmly believe that it should not be forced on the aviation community en-masse.
There is nothing wrong with the mode C system for those casual flyers who once in awhile pass through CAS, for those using the services of controllers and flying IFR then Mode S makes sense allong with the promised "extra" facililites it provides. But in the open FIR for flyers who never enter CAS I question the need.