One thing to bear in mind with the concept of automatically deploying liferafts; unlike floats, which are tested and certificated against inadvertent inflation in forward flight, the consequences of inadvertent liferaft deployment are not worth thinking about.
On my current type, the liferafts are externally mounted in conformal pods below the main cabin entrance. If one inflated in flight it would go through the disc, and that would be that.
Also, if the deployed on initial impact, while the aircraft was still running and possibly 'bobbing' about in rough seas, there is a good chance they would be destroyed.
Having said that, if manufacturers are going to put them on the outside, they ought to give the crew a means of deploying them from the cockpit, rather than from the outside! No names, no pack drill!!