I agree it needs more plants, but once those swords start taking off, they will stuff a 29gl to the max if you let them. Some of those plants look to be on their last leg, forum members here send out high quality plants usually in large quantities, look for "trim time" threads in the swap and shop. You have plenty of light, all you need now is pressurized CO2 to get the most out of your light.
I have to admire any S.American tank, I do the same given the parameters of my local water, now using reconstituted RO/DI. Some of your plants aren't S.American as pointed out, but I think you know that. I've reached a point where there are certain non region specific plants I will use as an exception, purely based on my own aesthetic reasoning, like Val nana rather than V.americana, it's more pleasing to my eye and a tank with any type of val is going to look S.American if the rest of the theme is there. In all actuality, if our SA tanks were true to most of the Amazon biotopes, we'd have an ugly tank full of mud and dead leaves with a few sticks laying around.