I challenge your assertion that all home NAS devices don't offer proper airflow to keep the drives cool. My drives are hovering around an average of 93 degrees, which seems to be pretty good from what I've been able to read up on (you didn't answer my question about what you thought was an acceptable range).

And those are temperatures in my rather warm office. Where my NAS sits it's regularly 78 degrees (F). When I open up my Synology's front cover, I can see a fairly generous amount of space around the drives, particularly at the ends. The cover its self is designed to let air in through every edge, with the fan being directly on the other side of the unit. It seems that the hottest drive is the one that's farthest-right and furthest from the direct airflow, so that makes sense and is unfortunate, but it's still well within range, IMO.

*edit*

I just tried upping the fan speed in the Synology dashboard, and now all drives are 29-33C. That's with the fan at "full-speed mode." Previously I had it on "quiet mode," and there's also a "cool mode." Full-speed is a tiny bit too loud for my taste (but really not too bad - I could live with it), so I'll probably back it down to cool mode.