The PDF format is becoming every day more a vehicle for malware diffusion and hacking. Didier Stevens - a Belgian by the way - has proven another time that you can do whatever you want through manipulated PDF readers (by using the features - not necessarily bugs).
He has made a proof of concept by which he has stolen files from a local computer that was contacted through an infected-hacked PDF file.
Encryption should become the norm or some form of identification before you get access to important files.
It is just a shame that Adobe is killing the PDF format this way, but let no one blame Microsoft afterwards that people will look at its formats again for safe standards because Adobe did this all by itself.
The best thing Adobe can do is give us back a stupid read only no script secure Adobe reader and PDF format. Like in the good old days.