Hello all! Julien this weekend was at the conference in Riga and we talked with him exactly about this, how it could be handled and stuff. The bottom line of our discussion was that I expressed the opinion that things should really start to move as of 5.5 - postponing it will not make any difference, because people will start to move only when it starts to generate some warnings and errors. Until then you can educate them as much as you want - they just ignore it. Everyone who was susceptible to education is already educated :)
Just my 2 cents. P.S. Kill the PDO too, this topic was also was discussed heavily.