Hi, madjoker15,
one thing to bear in mind is that it's no use expecting a newly planted tank to look anything like it will once the plants have had a chance to grow and spread out a bit.
Even high-tech tanks can take months to reach a level where ultimate results begin to become apparent, depending on plant types and other factors.
But Mother Nature knows what she's doing, we just need to have patience, and supply basic requirements.
And as nosoup4you suggested, that big rock could go angled in the back corner - even on its side, if it sits OK and you like it that way.
I don't know what horrible experience you had with sand, but, from what I've heard, the odds are pretty good it was either fine sand that kept getting into the water column to clog and ruin your your filter, or that went black and anaerobic, producing reeking gasses poisonous to fish - or both.
Sand is very dense, and unless lots of oxygenating plant roots reach throughout, anything much over an inch to 1 and a half inches deep may develop problems.
It may also be a good idea not to compress it under rocks, but to try to work such things down to the tank bottom.
I know nothing, and have never used sand, myself, but many have, often with great success, and I've heard such issues mentioned.
I had the same problem with Moneywort - which is what the currently rather stalky-looking plant with rounded single leaves, now placed along the back, looks like to me? - that you seem to be having, with many of the older leaves dropping off.
If it was grown emersed, it may take some time to recover.
I don't know if you know that it's a great ammonia-sucker which will help with your water quality, but I don't think it's likely to get very bushy.
You might like them better grouped off to one side, with something that will get bushy along the back.
I don't know what your lighting level is, although your plants did look healthy.
Some very experienced people have suggested ground cover and if you could find something low, leafy and bushy, you might really like the effect.
The trick is finding something suitable.
People have apparently grown Glosso under 2 watts per gallon in low-tech tanks, albeit more slowly and often more upright than the crawling effect it's known for.
Might be more than a bit of a risk, though, of it's not doing well in your tank, which would prove a waste of money and a hassle chasing out little bitty bits of rotting plant matter.
The previous suggestions made above included crypts, Wendtii Green and/or Red, as mentioned, being popular low light and relatively hardy fore/midground plants.
Crypts do tend to melt after transplanting for some (but not all) of us, despite gentle handling of roots, but generally do come back eventually (never chuck out a crypt root unless it's mushy and obviously dead) and are worth a possible wait.
Dwarf Sagittaria Subulata is grasslike and will also grow in low light.
Dwarf Marselia, 4-Leaf Clover, is lovely and also low-to-mid-level lighting in its requirements - but all such plants take time to spread.
Of course, if you could afford it, a mix of these might look fabulous scattered throughout the fore- and mid-ground of your tank even before they sent out enough to growth to cover the ground.
And one order of each might do it nicely, strategically placed, if money's short as it so often is.
Don't know if any of this is of interest to you, but there it is anyway.
And whatever you do, have fun.