[Fred Brackin]

In addition to what others have said Wild Talent first came into the system early in 3e as "Natural Spellcasting" and was later gneralized (still in 3e). The costs then were purely eyeballed.

It (like much of the rest of the Powers system) was brought into 4e with minimal re-skinning. The Advantages of the Powers system are full of peculiar and dubious costs and other characteristics.