I agree with all of the above: RIM are making a very weak case to attract developers.
The Playbook is cute but reaching the end of it's commercially viable life, at least until some upgrade is released.
The £198 price-point is good, but who in their right mind would buy a Playbook in preference to an Asus Nexus 7? Who would develop for BB knowing that most users will be commercial (with locked-down units that cannot buy stuff) or trailing-edge late-adopters who have no interest in apps.
It's just not a winning proposition.