Building the Item out of 2 Amplifying Tome is horrible since you lack space as Support. Starter Item+Boots+Mythic+Control Wards = 4 Spaces full early on. Now those 2 Items build out of 3 components, which makes no sense. The problem with blasting Wand is that 850g is not super easy to generate at once as Support.
As Support you always want a very cheap item to build in a still cheap item (Faerie Charm -> Forbidden Idol) OR Amplifying Tome -> Fiendish Codex.
Supports rely heavily on Ability Haste (Cooldown Reduction) so I think it would make sense to give those Items at least 10AH.
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