Thanks for all of the feedback!
One thing is clear: the majority of the KA Community is NOT into random or low drop-rates!*
It's ok if only 1 or 2, maybe even 5 or more top-gemmers to get the highest reward. Top rewards should be hard to get, IOW costly even in FTP games. But, events need to be fun for moderate & free players, too, and fun enough to keep the whales happily gemming for their exclusive rewards. It's a balance that all game developers want to achieve. (Heh, I probably wouldn't be here if I knew the key to balancing!)
If the developers want to keep random drops in LTQ-type events, maybe they could code the drop-rate to increase thru the course of the event. For example, weaker NPCs in lower quest levels would have low drop-rates, like 20-30%. As we proceed thru the levels, the drop-rate would proportionally increase: higher levels that require more energy for each kill would have better chances for getting drops, closing in on 100%. For all I know, maybe they already do this... just suggesting since I don't know.
~signed, clueless about KA metrics but love the game!
*edited "gambling" to "random or low drop-rates."