Ideas you came up with are interesting, I got several favourite ones, but...
To be honest, you seem to care more about your perfect imagination of some heroes rather than how their mechanics.
For example, Ahri. Although you called her just "an another mage with extra mobility" you didnt change neitther her E or R, her transparent abilities. What you did change, was her Q - you turned it into Fiddles'sticks drain. It may be filling your idea, but seems to be completely irrelevant with her. Here is why:
Ahri is, like you said, just an another mage with extra mobility. Fiddlesticks is not even similar to her, because his whole kit is to keep an enemy close with his Q, while harrasing him with W and R. He is about building glass cannon and screw around teamfights, causing chaos and tons of damage. His W is for him to give him an advantage during single target trades, otherwise he wouldnt last long enough. He is like - go in and kill or die
And here is Ahri. She is really hard to catch because of her ulti, she never stands in one place for long. Her Q is a team shreeder if used right, however, his right use requires good positioning - which has never been so simple with any champion. So you would replace her Q with a drain, just because it fits better into her whole lure-use-forget lore. It would be totally useless on her, because as I said, she never stands still for long. Channeling is an opposite thing to mobility.
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