It looks like a possible interior change is coming. This is based on spy photos that have come out showing a new interior to the F150 for 2021. The most interesting thing is a Tesla like center dash infotainment screen but in horizontal format.
There is a possibility that this will carry over into the SD lineup.
This alone would be enough for me personally to wait for a 2021 Tremor; that and I am waiting for the Silver Spruce color.