You should know SD3 uses more than one tile, so they're able to pull off the random look with bigger blades much easier.
Also, while they simply have 'puffs' of thick grass, you're using nothing but thick grass. Your grass doesn't have to look tended to, but yours looks like leaves more than grass. Remember, grass grows up, but if it's too long the blade will collapse on itself and arc downwards, forming like a crescent instead of just grass growing in every direction. I think that's really what you're missing with this.
