OS X Technologies :: USB Drive Spin-up Causes Frequent UI Delays?

There appears to be a rather serious (IMHO) design oversight in OS X's file system routines, as concerns the handling of external drives with power-save features. I've never bothered mentioning this online before, as I've always expected it to be resolved, "in the next update". But I've been waiting now since 10.4 Tiger and nothing yet. So I figured I'd raise the issue in here, at least to see what others might have to say about it. 

I keep an external (Seagate) USB drive connected to my personal iMac, for use mostly by Time Machine. I'm sure I'm by no means alone in this practice. :-D The drive is, of course, modern and nice enough to power down when not in use (well, "spin down" at least.) The trouble is, even though OS X's disk caching system really ought to know (IMHO) that the drive has not been unplugged or accessed by anything else since OS X itself last did so -- alas, for the likes of Save As ... dialog boxes, we still get a several-second Finder UI "lock up" -- usually accompanied by "the spinning beach-ball of death" -- while the OS merely waits for the external USB drive to spin up and say, "Yup. Still here. Nothing has changed and all is well. Carry on!", before finally presenting the list of places I might want to save my file at. 

This happens in all applications, apparently any and every time the OS wants to refresh the list of available storage devices. So it's obviously an OS X cache/driver issue, as opposed to anything in user-land. Wouldn't you agreed? 

I guess my first question would have to be, "Is there something I've not been able to find, which I can in fact already do to fix this problem?"

I know it's not just me, actually, because we have five (5) Macs in and about the home office, which all exhibit this highly frustrating behavior. Two use Seagate USB drives (one is 5.25", the other 3.5") while two others use Western Digital drives and the final has two Samsung drives, in custom enclosures. In fact, that last machine -- with an second drive solely for additional mass storage -- has us waiting while both drives spin up, in turn, which is frankly just terrible.

Indeed, the retired TV producer gentleman who owns this particular machine, swears that his iMac is, "the worse Mac I've ever owned", solely because of this problem of, "... constant $@#% delays ...", as he puts it.

Meanwhile, I've been trying to convince the old fellow that doing a full system re-install is highly unlikely to fix his problem. He harkens back to the days of OS 7?P.S: While I remember it -- there's another problem you might have come across, whereby if an external display is connected but turned off, the UI (mouse pointer etc) continuously pauses about even second or so, forcing me to either unplug the external (DVI) display or leave it turned on, even when I'm not using it for hours on end. This one is not nearly such a biggie as the USB drive one, in my view. But a curiosity, none the less.

Info:
iMac, Mac OS X (10.7.4), 16GB RAM