There’s only drag, bounce (restitution) and friction. I think it would be useful to have a mass (weight) property too.
I know there’s only density in box2d, but I think mass would be more understandable for flowlab game creators:
Mass = density * area size
That means when the block gets 4 times bigger, you’ll have to make the density 4 times smaller so the mass keeps the same. The mass will automatically be adjusted when you change the object’s size. So only advanced game creators will change it.
In a situation like this, I just use individual motors instead of gravity. It simulates heavier or lighter gravity, but your suggestion is more simple of an approach using the dials instead.