Could this be the dawn of Starfleet's ringship renaissance...
UPDATE: Mark has been posting some interesting comments on the design:
The ring itself will stay in this form. The lighter uppper part is probably going to be a translucent or fully magnetic confined plasma stream.And thoughts on the future of slipstream:
As for the ship design requirements of QSD: I would compare it with the first airplanes, they all followed a certain guideline. Most if not all with dual or triple wing design to get enough lift. Quantum Slipstream ships in this era all are made narrower to be more efficient within the conduit. I'm pretty sure that in a span of 20 years (in universe) the ships can have necks, full saucers and wider shapes again. The limitation in design will fade away because of evolved understanding and technology. However most Andorian and Vulcan ships have always been more narrow, so they probably wont change much anyway.