I’d also like to see heating and cooling added to the energy dashboard.
Honestly, I think the first place to start would be a simple graph showing the heating and cooling time per hour each day (plus per week, month, year, decade, century, millennium, etc) I think this is one of the things my nest thermostat (the new one in the google home app) does incredibly well and I would love to see HA copy their homework.
Things I like about the Nest implementation is it always displays a fixed period (00:00-23:59), if you somehow have heating and cooling on the same day they stack and show the corresponding colour and the interface is just clean. I’ve tried replicating this in HA and I have not yet come close.