this drive seems to get much hotter than others
Have you verified that with a surface thermometer, or relying on the internal thermocouple in the drive itself? It
could be just a faulty thermocouple (or rather, the circuitry measuring it).
In the worst case, its motor grease is aging making it sticky (increasing its sticktivity) and increasing power draw and thus increasing heat generated.
Still, my experience with electronics and heat is that very often they are poorly designed for heat dissipation.
For sure, that's why I started building my own.
I've seen many that try to have laminar flow for the processor heatsink. That can easily cause the regulators near the processor on the board to get too hot.
I typically use one additional fan at low RPM inside the enclosure to ensure non-laminar flows and sufficient mixing, plus a few baffles on the input fans.
It is not difficult to do –– although I so wish I had had a thermal camera to check! –– so it is kind of surprising big manufacturers get this so wrong so often.
As for putting the drive to sleep via software I just do not trust it because the OS can access it beyond my control.
In Linux, the kernel correctly resets the drive from all sleepy modes automatically, so it was never a problem. That is, I've never needed to "wake up" a SATA drive.
Some drives, like WD Greens, are pretty aggressive sleepers by default, so adjusting the settings (also doable via
hdparm in Linux) is definitely useful.
What is clear is that putting the drive in a regular 3.5" bay with others stacked above and below will not do.
That's how I had the three drives in my quiet setup, but with an input fan (Gentle Typhoon was even better than Noctuas, due to the semi-obstructed flow) in front of the cage. Spreading them out more would have been even better, but there was no room in that cage. Airflow on the sides of a HDD drive does not help much, what matters is airflow on both large flat surfaces.