I would prefer to leave SBD well enough alone for now. Though, like others, I can see my opinion changing on that as the platform develops. Right now there is no use for a pegged SBD, maybe that will change in some distant future.
To be honest, if the witnesses want to tinker, I'd suggest dealing with the real problems on this platform. The ridiculous state of affairs that sees and few dozen people holding 95%+ of steem and the rewards mechanism that allows for so much abuse while almost guaranteeing endless flag wars. Those two things will hamper if not destroy this platform in the long run.
Steem is the only show in town at the moment and as such is has a Blackberry type position in the market. If those things are not fixed by the time the iPhone of the social blockchain space comes along and it will. Well it doesn't take a rocket scientist to work out what happens next...