For those who don't want the requirement but want the potential benefit could use static if's (you know those things that so many people forget even exist) and "requires optional" (something not seen nearly enough).
In terms of efficiency there is not a lot to be gained, but by saying "a few dozen" handles will be saved that is underestimating. Order events, spell events and death events are quite common among a multitude of resources, the number of handles saved can easily launch into the hundreds and larger maps even more.
Surely using something like your http://www.wc3c.net/showthread.php?t=105374
is quite useful for handling that corner of the market, but this is more extensible.