In general I like the design. Namely that Starfleet would be nostalgic enough to build an entirely new facility, but harken back to a Cardassian design when they could just as easily build one of their normal designs.
It's kind of hard to make out what that green is, but yeah I suppose an arboretum would be reasonable. And the rim of that window appears to be bright like it's a force field.
I can't tell if it's the angle, but the central core underneath looks to be slightly off kilter, as though it's farther back than that dome underneath. But wouldn't that be all one structure?
I guess the only thing I'm a little confused by is the vertical rings. Not that they exactly made a lot of sense on the original station (shouldn't they have pointed outwards?). Seem like they'd be a hazard to navigation. Or simply block the view. I thought I remembered reading that there would be docks all up and down those rings, but would they be stacked up more on the vertical part? Or is a ship supposed to turn perpendicular to the horizontal plane of the station to link in? Like towards the top?
Also, is it me or is that ring above the terrestrial enclosure not actually attached to the rest of the station?
And must the Excelsior-class the oldest serving?!
After the Mirandas were seemingly retired to make way for the Merians, it appears the Excelsiors could be the oldest class still in operation. Total speculation though obviously.