For me, and bear in mind I have a different idea as to what looks good to other people, when I look at that first tank shot my eye is immediately drawn to the mag scraper and the weir wall, mainly due to the fact the scraper is white on a dark background and the weir is a bright blue again against a darker background.
I wouldn't and dont leave my scrapers or glass cleaners in the tank, at all. I'm convinced that they will eventually rust and leach something into the tank.
I would also really love to cover that weir in as much rock as possible, yes this means that essentially you will have a central column of rock around your filtration but that means that the sandbed is opened up more, I would then go the further step of hiding the equipment behind or around this rock wall/column as these also attract my eye. Alternatively i would try and encourage coralline algae growth on the blue plastic and scrape everywhere else. You can do this a couple of easy ways (NOT CORALINE IN A BOTTLE) next time you're at a LFS look for some snails that have this growth on their shells, once acclimatised to your tank scrape the shells in the tank water to release the coralline spores, this will then encourage growth in your tank.
I really like the last shot showing a sloping sandbed, if you could recreate that on the other side of the tank (leave that rock in as an outcropping at the front on that side) i think that it would help add depth to the front viewing angle and more interest to the side viewing too.
So other than those, what is it that you dont like about the tank? Lack of movement? Colour?