As others have said, SCH isn't a bad job. SCH is actually preferred in some instances because of their damage mitigation. As a WHM myself, the best setup in my opinion is to have a WHM and a SCH together because they compliment each others abilities. WHM cures for higher amounts and has a good AOE heals with Medica, Medica II (, and Cure III in some instances), as well as two heal over time spells to increase survivability of party members and allow us to more readily focus on the tanks with bigger cures.

SCH can put up damage mitigation on the entire party with Succor I believe, as well as a stronger one on single targets with Aldo (and crits put a very strong shield up). The fairies are also key to SCH healing prowess, you essentially have another healer casting cure/physic on party members, alleviating some stress on the healers in the group. Plus, depending on the pet, the party can get +spell/skill speed, regen, and a couple other buffs from the fairies.