I feel sorry for clerics every time I see one come limping past me, waving their arms and screaming like a little girl, with twenty imps and three demons all trying to eat their face. Repel is good for those situations.
Yup. Tab slotted it'll reduce something like 75% of the first hit. This isn't all that hot early on, but later when you can easily get hit in the face for a quarter to half of your total hit points, it can be worth toting around.
"Group was all rogues" There's your problem. Get a CW to control the dangerous adds while you burn them down. If the cleric is swarmed, the wizzie should be there to support them.