It's more that the mobo needs a rethink. Putting the M2 sockets somewhere else would be a better idea. Putting them in a line across the back by the slots or clustered in the bottom slot area would allow for better temp management.
One thing nice about physical health sink plates covering them. If they're clustered together I can see a way to make a cooler that fits a standardized add on cooler that fits a section of M2's.
By design there's 3 M2 slots in red but, if OEM's took the orange area or bottom 2 slots and made it into a cluster that's standard you could fab a heat sink for 4 M2's and keep them away from the heat producing CPU / GPU area and keep them cooler. Losing those lower bandwidth slots wouldn't be a huge impact either. Also, since all OEM's use the lower slots for lower gen cards anyway it would free up some lanes for use in the other slots. You could still manage to fit 4 cards onto a board for use. Or some people would still be able to get dual GPU's into that space if they wanted to.
There might be some complaints about how long the traces would be to the M2 complex but, if they did it right they should be able to pipe in enough high bandwidth paths to that location to hit the CPU. Otherwise move the chipset from the right side to another location and orient the M2 complex there.