You could:
Use sliding collisions as you are doing
When in contact with terrain "entitycollided" do a downwards pick with "linepick" check the number returned by "pickedNY" the larger the number the steeper it is.
You could then add a controlled number (multiplied by the number returned) to your gravity constant when in this state to force a faster/lesser/none existant slide.
Not very "physics" but it works.
Use sliding collisions as you are doing
When in contact with terrain "entitycollided" do a downwards pick with "linepick" check the number returned by "pickedNY" the larger the number the steeper it is.
You could then add a controlled number (multiplied by the number returned) to your gravity constant when in this state to force a faster/lesser/none existant slide.
Not very "physics" but it works.