Im just poking in here to say that most Tier Lists are arranged from S to D tier, but I spose that is a matter of preference.
Also, You seem to be forgetting tanks... I recommend switching to a single tier system for each character Archetype. By putting Tier 1 Jungle Shaco with Tier 1 AD Carry Tryndamere, you make it seem as though a Shaco can take on a Tryndamere.
Finally I would avoid making things as "cut and dry" as you are trying to. There are various jobs for various characters, at which each character excels at. By simply putting "AD Carry" or "AP Carry" and covering every mage in those areas, you undermine jobs such as "Anti-Carry" (Which 'Tier 5' Malzahar would excel at... probably an A tier).