That's the move that'd generate most annoyance among existing users, especially those who buy a PS4 just before the new one comes out. Would that affect the brand/momentum in a bad way? Probably not. i guess it'd attract many more buyers (perceived much better value) than casualties.
Well if we are being honest you'd be an idiot to buy a PS4 in the next 4 months or so...unless you simply don't give a shit about better specs..