I've seen static shots of this design, but the video was incredible! It's an upgrade over the original Oberth-class in several respects. I actually prefer this design over the Sculpin-class on which I based the Albacore-class 13 years ago.
Yes, the Oberth used the struts for access to the secondary hull. According to most sources, the secondary hull of the Oberth is comprised of a highly efficient sensor array and scientific labs. Engineering on the Oberth is in the primary hull.
The USS Johnston is different from the Oberth in several respects - engineering/hangar bay in secondary hull, more fire-power, somewhat larger, faster impulse and warp. (Oberth could only make warp 6). If it had a central neck connecting the saucer from the secondary hull, it would be perfect.
Here's a weird coincidence - my last name is Johnston. No, I don't know the artist/creator of USS Johnston.