With regards to the question about ACARS, my understanding is that ACARS based technology is here to stay for the short-term future. It will eventually be replaced by applications from the Aeronautical Telecommunications Network (ATN). A number of trials / simulations are currently being run which are related to the implementation of ATN.
If you wish to know more about one of these particular trials, have a look at the EOLIA web site (www.eolia.org). EOLIA, European pre-Operational Datalink Applications, is a multi-national project examining the initial implementation of ATC services using datalink messages passed via the ATN.
Regards,
Euroc