As title indicates, I'd like to suggest that right-clicking on ground cover objects while in Survival mode does not change them to a different variant. I believe that it's strange to be able to right-click on a bone (or rock, etc) in Survival and have it change.

I'm trying to figure out the best way to handle how groundcover drops and which models can be used. Maybe might just make it so that it places a random model that cannot be changed.

I would honestly be fine with that, but it would be even nicer to have some way to select which variant is placed in creative.

A suggestion could be to just have it so that when the ground cover actually gets placed by the player (And/or during generation), it selects a random variant that can not be changed unless it's picked up (The default shift-right-click behavior) and then placed back down. This would avoid the out of place nature of just right-clicking the ground cover to change it but would still let the player selectively choose which variant to use by just breaking and replacing or picking up and placing it back down.
However, that might be an enormous pain if you want to use a specific ground cover in Creative mode, so I'm not sure how loved that feature would be.

I was thinking of exactly that. I can also make it so that the player can change the model when in creative mode.

Implemented in v1.3.0!