waterflow is imperative in keeping the substrate and tank in general clean, a extremely dense yet manicured tank is a great balance, I totally agree, you could use alot more plants, personally i love that sword and would plant them all over the back corner and side of one side of the tank and start tiering down, however swords tend to reproduce like crazy via runners for me, and I'm sure it would be no different for you, so trimming every few days is pretty much a must, so go crazy and add more, just remember trimming is a good thing, and make sure there are no dead spots in flow because un eaten food or dead leaves will find it and stay there, the heavier your plant load the harder it will be to clean those areas without damage, i tore down two tanks because of this and it was a big lesson learned, however i love lush dense plantings, just even it out by adding a power head to get dead spots, and trim to where the plants are low, besides your background if you want them tall, which amazon swords look amazing like that, also if you can get one add a tiger lotus in front of the sword about 2-4 inches away for a nice red contrast =] another plant that grows fairly large and will require trimming to keep looking great
also a good background for that tank besides the swords in a corner would be blyxa A, or jungle val or even a giant hairgrass wall