I'll just say that I'm definitely not a dedicated aquascaper. My tanks evolve around what my fish need, what I like (the lush look) and a that doesn't look to bad approach. So keep that in mind.
So from my untrained eye the edges of the sand are the thing that stand out. I'm not sure whether a more natural looking stone would help but it's to linear and bold a divide at the moment. I see you need easy maintainence so my first thought of softening it with a short plant might not be the best for you but I think that boundary needs attention. You could use a few buce or small leafed anubias, or even some moss on nicer rocks to help, just don't go for a linear line of them, randomly placed along the rock boundary. If you mixed these with a different darker stone (mixed sizes so they rest together better) but smaller more scree type pieces that give a less uniform natural appearance.
But apart from the sand area I think it looks really good and will improve once it's grown in, unfortunately at the moment the stark contrast is what makes you focus on the border between the two which is why I think a more gentle transition is needed.