AP Markman and Itemization

Hoping for a reply from Riot on this one, in terms of roles what is Riot's stance on AP Marksman and maybe introducing new items for said role?

Having a choice between going AD or AP Marksman would, not only, make bot lane more interesting, but open up other lanes as well. As it is now, the only true AP Marksman is Teemo, but isn't really fit for duo lane. Sure you can build AP on Miss Fortune, Ezreal, or Kog'maw, but they have too much of a mage playstyle. Currently, Marksman that have AP scalings can build AP, but sacrifice a lot of sustain by not being able to benefit from Lifesteal.

Possible AP Marksman Solutions

1. If a majority of a Marksman's basic attack damage is magic damage, Lifesteal will heal according to magic damage dealt instead of physical.
2. Merge Lifesteal and Spell Vamp into a single stat. Abilities will heal for x% and basic attacks will heal for y%. This might be risky, simply because all champions would be able to heal from basic attacks and (Vlad says hello)abilities. Maybe champion-specific tunings of stat?(Not 100% how to make work without problems.)
3. Better Itemization for AP Marksman.

As said before, AD Marksman that can be built as AP are either inferior to AD counterparts (not true for all, namely Kog/Ez), weak in general due to not being a genuine AP Marksman. Needing decent amounts of AP for damage or having bad laning phases. AP Marksman would probably want to have increased benefits from AP to compete with AD counterparts. Offensive Items would also most likely need to focus on magic on-hit damage. Defensive/sustain items would either have to make Lifesteal proc on magic damage or have unique passives on items to prevent mages from abusing them or being too strong for others. Key advantages and disadvantages would need to be emphasized.

AP Marksman Passive Idea

1. Magical Arrows (Passive) Basic attacks now deal magic damage as opposed to physical. In addition, basic attacks gain additional damage equal to 10/12/15% ability power. (Straightforward, but different since it converts AA dmg from physical to magic.)
2. Sparks Fly! (Passive) Every other basic attack grants a Spark, storing 15% basic attack damage. After obtaining 3/5/8 Sparks, your next basic attack triggers Sparks Fly! For 5 sec, basic attacks will consume a Spark dealing the damage stored plus 15/35/60(+15% ability power) as magic damage. This effect has a20 second cooldown. (Unique ramp-up passive, maybe for a burst-cycle style AP Mark?)

AP Marksman Item Ideas

1. Zephyr's Recurve: [Blasting Wand + Dagger + Dagger] 40% Attack Speed; 60 Ability Power; (Unique Passive) Buffeting Winds: On hit magic damage deals 70% additional damage plus 5[+20% AP] magic damage over 2 sec. [Offers sustain damage plus a unique effect]
2. Doran's Wand: x health; +x on-hit magic damage; +x AP [Possible AP Mark. Starting item?]

Feedback is welcome, I would like to hear others' opinions on AP Marksman.