Security is a significant issue here.
Whilst I would prsonally welcome an all informed public, I'm not so sure I would want todays terrorists realising that all aircraft inbound airfield A fly over reporting point B at FL C. I suppose you would continue to counter this argument with the fact that you can validate this data by RT alone - it all comes down to the level and accuracy of detail that is readily available.
It is possible to filter sensitive flights and then promulgate the sanitised data on the internet. However, why should this be done, at cost, just so you can follow your hobby? Propose a business case to CE NATS and see how much he would charge you for the privilege.