I simply wanted to put forth some ideas that I hadn't seen elsewhere. Admittedly, the target is probably off in several places, but the concepts themselves could still be put toward a fresh target.Not to be the Debbie downer or anything but if you don't play the class then you probably shouldn't give these tome ideas...
The idea of the gods sending down a holy book for the Cleric to glimpse during his/her healing duties, for example, seems like it'd be a fun thing to look out for during battles. Using the same concept, the target could easily be shifted from healing spell speed (which you say is useless) to something like a boost to group weapon proc rates, substantial increase to DB's chances of going off while the book is present, the group being partially shielded from spell damage, or whatever else might be deemed appropriate. A savvy dev could probably think of a dozen other things that'd probably be even more interesting and/or useful while still using the "book falling from the heavens" or some cooler variation of that as the starting point.
Again, I may not be a guru of all classes, but I still think several of these ideas have strengths at least at the concept level, and I'm proud to have been able to share them here. Even if none of the above are deemed worthy of pursuit by the Powers That Be, I still had a lot of fun racking my brain to come up with them.
Thanks to everyone who has given feedback.