Wizards channel their spells with toughness. Their Willpower is reduced by x for each x of worn armor.
The channeling part (at least on p31 for humanoids) states that a wizard can use up to their total characteristic value when channeling a power.
Since armor is a Toughness enhancement, does wearing more armor allow for an increased amount of channeling? E.g. a wizard with toughness 2 can channel for 2, but when he's wearing medium and thus has an armor bonus of 2, does that mean he can channel for 4?