The large heatsinks are mainly for people that don't have heatsinks that ship with motherboards. Everyone is trying to make coolers for early adapters and that mainly covers people that need to use the performance available for long periods of time without thermal throttling. The motherboard heatsinks were designed very well and they are much smaller than the aftermarket and included (with drive) designs in most cases.
The big difference between the previous generation and the new generation really comes down to workloads. Everyone is hating on these heatsinks and saying Gen5 runs hotter but it doesn't. The M.2 power limits are the same, the lithography node is the same, but the workloads have changed. There hasn't been a reasonable way for you guys to run a DirectStorage game for a few hours. The DirectStorage workload is more like an enterprise workload than what we had before on the consumer side. Before, we would burst data and then the drive would go back to sleep or move to a lower power state. With DirectStorage, the workload will request data from the drive at several gigabytes per second and for as long as you play. That can be several hours!
To avoid throttling in this workload, you need a larger heatsink and that is true for Gen5, Gen4 and even Gen3 drives. Just because you are not worried about DirectStorage now doesn't mean we will ignore it. If we ignored it then people would complain when they played a DirectStorage game later on. This is one of those things where we just need to say, "Trust us, we know what we are doing and why we are doing it."