More Ability Power / Attack Speed

I don't know about anyone else, but it's quite frustrating being a Mage or other AP oriented champion and then wanting to push turrets a bit faster. Since attack speed is not generally part a Mage's build. So I threw some things together last night that I thought might possibly become an addition to the game.

Chem-baron's Guard 3500 gold

70 ability power 250 health 40% attack speed

Build path: Stinger 1100g Oblivion Orb 1500g Chem-baron's Guard 900g

Unique Passive- Superiority: +15 Magic penetration

Unique Passive- Miasma: Damaging an Enemy (Champion?) with a spell or ability creates a volatile cloud of poisonous vapors in an area for ten seconds dealing 5 magic damage +5 per level +10% of ability power each second to those that remain in the area. Cool down 5 seconds. Only one cloud may be active at a time. Deals 50% reduced damage to minions. Caps 25 damage per second VS. monsters.

Radius increases 20% of ability power, 50% attack speed capping at a total radius of 450

I had a few other idea but I figured I would start with this one. I don't know a lot about how everything works, but I sat in the items collection and tried to make something I thought I could see in the game that wasn't just broken and that plenty of champions could use. This is my first post to forums or sharing this kind of thing so please be gentle.