I tend to agree with the sentiment behind the restrictions on parking permits: If you have access to off-street parking, you don’t need an on-street permit.
Is this even a big issue in Somerville? I've lived in two spots in town - Between Davis and Teele Squares, and in Prospect Hill - and on-street parking has never been an issue. Not even close to the way it is in parts of Cambridge and Boston. And isn't some of the functionality intended to allow residents to access other sections of town by car? I always assumed that that's part of the reason for not restricting parking to the zones specified on the permits. I'm predominantly a transit user/pedestrian with a car for weekend/late night trips, but I do occasionally drive to other neighborhoods in town for a variety of reasons and I'd be pretty upset if that ability were impacted by permit changes. Especially since I'm not really seeing the need.