As a Roblox developer, it is currently impossible to add mass amounts of ground cover to terrain.
There needs to be a built-in system to add ground cover such as grass, flowers, etc to terrain en mass. This ground cover should be optimized so that large fields of ground cover do not adversely affect the game performance. Dynamic ground cover that moves naturally (like wind blowing through it) would be a bonus.
If Roblox is able to address your issue, how would it improve your game and/or your development experience?
In modern games ground cover plays a huge role in the visual design of a game. Without it, games look empty.
One of my games is made up of Smooth Terrain that was generated at the “massive” size. Even though I have hundreds of objects and props in the game, it still looks rather stark without ground cover. I do not have a good way, or game engine efficient way, to add the necessary amount of ground cover needed to fill out the terrain.
Here is an example of the type of ground cover I had in mind:
