I personally hate moss walls, though I know they're popular in Malaysia and Singapore.
-Aquariums look nice if you make them look bigger than they are.
-In order to do this, you have to make it look like "not just a box"
-moss walls draw attention to the back wall
-drawing attention to the wall makes it look like "just a box"
However, moss walls made with cork bark/bark/bamboo/other rock instead of mesh can look good, the way they do in an a vivarium. Those walls have "multiple dimensions" that are "un-box-like."
Even that way, using a moss wall makes everything seem small. It becomes a "magnified scape" rather than a land-scape. It's like looking at tree roots instead of looking at the forest. Both can be pretty. You just should be aware of what you're doing.
If you want an easy to maintain area back there, I'd say stick with the glosso and plant some crypts or grass-like plants in addition in between the glosso. Anubias would be ok too as long as the rhizome isn't burried. Anubias "petite" could be good.