This change was necessary and long overdue. Requiring domain owners who send significant volumes of email to properly sign their messages allows receivers to more clearly delineate good from bad based on domain reputation rather than IP address reputation.
As more domains send email through shared IP space on transactional and marketing services, having the ability to attach reputation reliably to the sender domain is incredibly helpful in reducing abuse.
As more domains send email through shared IP space on transactional and marketing services, having the ability to attach reputation reliably to the sender domain is incredibly helpful in reducing abuse.