I'd love to see the ability to reduce temperature depending on the current extrusion rate linked into the 'minimum layer time' settings.
If I'm at a large area that doesn't need much cooling and printing as fast as my nozzle can cope with, I'll generally want at least 20c higher than the minimum temperature I can use to give enough heat into the actual melt for layer bonding and extrusion at that speed.
Conversely, if I've then got some small islands where the minimum layer time means the extrusion rate has slowed to 50% of my max, I may want to run the filament 20c lower as the time it has for heating in the hotend has doubled and I'm obviously struggling for cooling.
My thought is you could have a simple checkbox below the minimum layer time + minimum layer speed box, so you specify say 'minimum layer speed = X% at Y*c lower temperature.
If I put '20c' in that box, then at 50% speed it runs my filament at, say 200c instead of 220c, with a linear change between (so at 75% speed it does 210c, etc)