I don't claim to be an expert on Blackberry, but for me the real sell for Blackberry has always been BBM. Kids today all have mobile phones, and most of them in the UK have Blackberry's solely for contacting each other through BBM.
I feel that Blackberry could save themselves by targeting both those who love BBM, and those who want a simple, cheap phone. I think parents and kids would love to have a basic phone with a physical keyboard, BBM and a great new UI.