Smiting Blue Should Also Reduce Your Cooldowns
Getting mana from smiting blue is nice and all, but it's often not all that useful especially given that some junglers are manaless and how fast blue buff lets you regenerate mana anyways.
So to make smiting blue feel just a bit more useful outside of the plain old damage, I propose that smiting blue should also reduce the cooldown of all your abilities by 10 seconds.
10 seconds is just enough to allow most junglers to quickly repeat a spell rotation while not being too much to allow CDR Lux to double ult.
The only possible abuse case I can see is Zilean quadruple bombing people, but then again who jungles Zilean? :D
Alternately make it a % amount, although that could get you into issues with being unnoticeable for ordinary abilities, and devastating for ultimates.