ok here are some pointers:
- top-off more often
- organize your stem plants into distinct bunches (btw, rooted ones work better as part of the aquascape, hornwort is really just a sponge plant IMO).
- get a foreground
- use plants with fine leaves. large leaved plants overwhelm small aquascapes.
hornwort: you should be able to find somebody, but dont expect something rare like an erio or something for it.
sword: sure. there are plenty of people into swords.
set up a trade or sale thread in the S&S.
i dont know your lighting/CO2/fertz ratios, but they should be good enough for some plants like rotala rotundifolia (hardy, and looks great), HM (can be grown as a foreground, midground, or thick background), and hairgrass (dwarf for midground, giant for background).