Lemme pitch a skillset-- I'll keep it short and to the point, tell me what you think.

The objective is a champion that feels like a ranged fighter and ability caster. It is an IMPORTANT design criteria that the champion not feel compelled to interact with his opponent pretty much exclusively by auto attacking over and over until the enemy does something, the way champions like teemo and tiny gnar work. Another important design criteria is that the champion should not provide as much single target damage as a ranged carry in fights, and trades that off for the ability to control how his damage is distributed and for some durability. It is important that both the durability and the target control offer windows of opportunity to the opponent.

Basically the champion should FEEL like he is an ability caster and he should FEEL like he is responsible for choosing the right tool for the job, so that the player can always be thinking "I could have done that better! I'll do it differently next time." In order to enforce that, each tool should also be weak in some ways so that it is possible to choose the wrong tool for the job. In order to make that decision even more central to the theme of the character, these tools should modify the way the champion interacts with his opponent even after he makes the decision to utilize it.

The passive plays a large role in making the champion feel less like a glass cannon / high dps champion and more like a ranged fighter / moderate dps champion. The ultimate is the gateway for all of the champions interesting decision points and gameplay.

Passive: If you were to critically strike an enemy champion, instead of dealing bonus damage on your next auto attack you generate a shield equal to your AD that lasts for 1 second. A shield can only be generated once every second. (note that you cannot generate a shield unless you are auto attacking someone)

R:(charge/release) For as long as you are pressing R, you are locked out of being able to auto attack. Releasing the button causes you to send a damaging pass through linear skillshot in the direction of your cursor with a moderate range and moderate speed. For every second that passes while you charge (up to a cap), you will generate bonus damage for that skill shot based on your attack speed, attack damage, and critical strike chance. You gain one use of your ultimate (as ammo) every 6 seconds, and can store up to 10 uses. If you fail to release the charge 5 seconds after beginning the charge, the charge is lost.

Q: (toggle) Active: your overcharge attack on R sends 15 projectiles outwards in a ~90 degree cone shape at the expense of (a ton of) projectile speed, instead of a linear skillshot. Passive: your basic auto attacks have much lower range but deal damage to everything in a ~90 degree cone in front of you.

W: (toggle) Active: your overcharge attack on R has double range but cannot pass through targets. Passive: your basic auto attacks have higher range but cannot critically strike (that is, they cannot generate a shield for you).

E: (toggle) Active: your overcharge attack on R bounces off of terran but does less damage. Passive: your basic auto attacks deal much less damage than normal but steal some of your targets armor and magic resist stacking up to a cap of X armor and X magic resist.

Notice that these toggles are NOT mutually exclusive.

You could have them all on at the same time if you wanted, but they each carry their own penalties.

For example, having both Q and W on sends out 15 projectiles at double the normal range of your overcharge attack, but with very low speed and cannot pass through targets. Your normal auto attacks with Q and W both on could not generate a shield for you but would damage everyone within a cone.

Having E and Q on instead would cause your overcharge attack to release 15 projectiles that each bounce off of terrain and pass through targets, but deal less damage than normal. Your auto attacks with E and Q on would deal damage to everyone within a very small cone for less damage than normal but generate a shield and steal resistances from everyone within the cone, very quickly capping at X armor and X magic resist.