These young co-pilots will get it alright, provided companies will approach the subject in the correct way.
They won't, they will do what they do now, try to fill their front seats as cheaply as they can get away with.
Is this to extend to private ops (ie will I still be able to go around in my twin in IFR using private privileges?)
I'm afraid you already can't. Under JAR all IR's are type specific, to fly a light twin you need to do a renewal on that class of aircraft, your airline jet IR renewal does not cover you.