Thank you all for the comments and suggestions.
Yes, the little curved thing is what is left of the Bacopa. I guess I'll remove the rest

.
The rock that most of you don't like is lying on top of the flat one. I was not completely satisfied with it when I set the tank up, either, and I had tried a few alternatives. Just taking it away doesn't work, because you need something to balance the leftmost rock of the right-hand group. A smaller rock looks weird. Somehow, I got used to it by now. But I haven't tried shoving it to the left, yet

.
The rocks are just collected from a (dry) Arizona creek. I thought the sandstone and its round, but slightly weathered surfaces should work nicely with the sand. You are right, the tank somewhat resembles a dry creek here, although I didn't have any mesquite trees to work with

. You also see quite often rocks lying on top of others. But I have to admit that the main reason behind the tank was having a playground for the cories, who like to plow through the sand. They usually keep it very smooth and clean, and all the irregularities you see result from me removing some algae below the sand surface before I took the photograph.
The tank is medium light (about 3.5 W/gallon) and low maintenance. The canister usually keeps the water clear. Algae are mostly removed by the inhabitants. I use some fert tabs for the swords. I try to keep them in that state so that they neither grow nor shrink (swords are one of the few plants that actually just shrink when they are unhappy). That's about it

.