While I use Shimano shoes for most occasions, on longer rides (100k+) use my Northwaves, which are radically different, effectively stiff road shoes but still with recessed SPD.
Here's what it looks like
The plastic substrate it sits on (I don't _think_ it is carbon) is not just very stiff like the shimano but pretty solid. Heel to toe, flexing in my hands, there is only 10mm of movement for anything below destructive force.
This has two effects.
1 - It appears to eliminate hot foot, at any of the distances I have ridden (max 250km)
2 - It adds another level of complexity to clipping in, requiring and adjustment from my standard technique. When you fail to remember this, the shoe slides off before engaging resulting in a pedal/shin interface.
ETA: I have VERY broad feet