I feel there should be a PowerToy applet to turn Segment Heap on or off.

This is a great idea, honestly. PowerToys is open source. There's a decent change that they would be open to such a contribution.

It is a crime that segment heap is over a decade old and still so underutilized. Gamers in particular go to such great lengths to tweak and optimize their windows machines for perf, but I still haven't seen that crowd discussing segment heap anywhere. It's more important than ever with the recent explosion in RAM cost.