Karthus skill, risk, reward of Q (Lay Waste)

I want to suggest the concept of different risk/reward mechanics and improve the focus on skill requirements. Karthus has been a problem for balance ever since I first saw him. Currently, he is feeble and easy to pick on. His poke can allow him to be too close and then he cannot do much since Q has a long delay and W and E are pretty much passive. I would like Karth to be able to have better trade for risk and reward with his Q. He's at the top of two steep slopes and past updates have made him mostly safe to play against unless he gets a lot of $$$.

Some or all of these would apply. Please read and understand all before commenting:

1. Vary delay and cooldown based on distance. If the enemy is in his face like Jax, let him use it faster. If the target is 2x his auto attack range, let the delay be 1.5 seconds with a cooldown of 2-3 sec. At short melee range, let it be 0-100 ms with a cooldown of 500-700 ms.
2. Vary the AOE region with distance a little. At the max distance, he will need to be more precise, but at melee range, the damage will be wider.
3. Vary damage with distance a little (15-25% too much?).
4. The AOE would have 2 circle ranges. The inner circle that is small and always the same size with X damage. There would be a larger circle that varies in size with Y damage. Enemies would be damaged with X+Y or just Y damage. Basically, there would be a bullseye where you get more damage done.

**High skill: **With the first 3 above, it should be rebalanced in a way that longer distance requires much greater skill, but gives greater reward. Since there would be longer delay, these skill shots could easily be dodged. It would require very little risk and only with skill, luck and/or assistance (CC) could he expect decent damage from this.

Low skill: At melee range, very little skill is required, but now he is in the danger zone. Currently, if Jax, Malph, or J4 attack him, he is good as dead unless he leveled up W/E enough. At melee range, it wouldn't change much, but getting in 2-5 very low damage, wide area Q's versus 1-2 standard Q's could help average it out.

His other spells? Well, Wall of Pain should have a much shorter range than the max distance of Q. If the player really is skillful, he/she will have to make the high damage, small area skill shots without his own slow. I imagine that Q would be up to 2x his attack range and W would be 1x his attack range. E would be up to 0.9x his range.

**Visual effects? **It would be cool if it looked like red lightning traveling along the ground right before the pop.

Just a real life example and not that cool looking. Still, it's something: http://www.geekation.com/wp-content/uploads/2012/12/Geekation_GolfCourseStruckByLightning.jpg