Don't Touch Him!
Just a quick little thought that spurred from the Annie Origin story. Though I know her update is far off and probably on the smaller side of the scale, a little idea popped into my head that sounded like something that might be a cool mechanic to play around with.
The basic idea is that crowd control and burst damage received cause Annie to drop Tibbers. Until she picks him back up, her mana is drained at an increasing amount the longer she goes without him, but her abilities are empowered an equal amount. Once it passes a certain threshold, her next ability stuns (yes this replaces her current system). Picking up Tibbers before reaching this point refunds some of the mana she lost while without him.