I think they are just bringing the licence system into line with reality.
I have worked on Line for a UK airline for nearly 20 years now. I have always held an Avionic extension to my approval. I can change boxes where no test equipement is required and more importantly I can raise ADDs against the MEL for avionic items.
On our station with 7 flights a day, we get help from a B2 engineer about once a year. Usually that is because he can read wiring diagrams much quicker than we can! I can't remember the last time we needed a B2 signature here.