I think the speedbooster idea would be great. It wouldn't have to go all the way to a full 5x focal length reduction, just compensating for the APS-C to Q crop factor, or even just partially compensating, would offer existing DA/FA lens owners (not just telephoto enthusiats) a better path to the Q system. Adapted lenses are a gateway drug to native lenses, meaning that this could potentially increase overall Q lens sales, rather than compete with them. The f-stop improvement would be a boon to the Q when shooting in low light, without threatening the better image quality offered by the larger-sensor cameras.
I think the accessory grip (with or without battery) would also be great, Olympus' two-part approach would be awesome. Maybe they are afraid that this will invite someone to try to lift a DA560 by the lens mount.
I'm glad to see they introduced continuous AF in the Q-S1. The 1/1.7'" sensor is well suited for casual video. While I think it would be awesome to build it into a serious ENG video camera, maybe just some minor improvements like continuous focus assist, more modern framerates, and adding mic/headphone ports on the battery grip would be sufficient to make this an even better alternative for casual and enthusiast video use -- to replace the camcorders that Ricoh used to build. Those are things that would require a faster processor, but the processor and sensors are getting faster all the time whether anyone wants them to or not anyhow. So it wouldn't increase costs that much.