So was asked to design a character with a weak will, dressed like a servant but would still be magically powerful.

So Pathfinder Sorcerer is the first choice right? But they start with a high will save.

Cross-Blooded Archetype lets one pick two bloodlines but you get one less spell known per level, and you get a -2 to your starting will save. (perfect)
So picking Arcane Bloodline and Dragon Bloodline
gives you one Knowledge skill and Perception as Class skills
1st level ability Arcane Bond for her Maid Outfit (of masterwork quality) which let's her cast one more spell per day and one reaching 3rd level enchant it like she had the feat Craft Wondrous Item.

Then it just falls for the starting stats and feat (half-elf)

So We have the stats 15, 14, 14, 13, 12, 8.
[Str 14 Dex 13 Con 14 Int 12 Wis 8 Cha 17]
and the feat Toughness for Hit points (HP: 11 total)

{wonder how many will noticed I filled this Description with nerd power?}