When planning a new trip‌ I frequenty find myself flying around with Simulator just to have the beautiful visibility that TerrainSafe offers. I live near the mountains and it's often hard to see with the normal map how wide valleys at a certain altitude are and which valleys are well connected to each. Just the other day I went from Munich to Basel and had to find a good route under Zurich CTR. 
W‌ould it be possible to enable TerrainSafe in planning mode as a simple overlay? This shouldn't be too much work since it's already implemented and it would make planning so much easier. 
T‌hanks! 

Maybe the projected track bar ahead of the aircraft in flight could go yellow and then red as you get closer to the terrain?