Rotala? I would never have envisioned that for this scape. Rocks are a bit low for a high growing bushy stem plant IMO. I liked the Blyxa japonica or a nice thicket of cryptocoryne, maybe even Downoi or Erio.
Should be interesting to see this develop with that stem plant selection. I have been amazed before by people on this forum and some of the scapes that they pull off, so I wouldn't be surprised if it happens again! LOL!