I've never found spellspeed overrated in the least. I pair up a lot with WHMs who have great healing power but end up dropping tanks because they can't get the spell off in time.

Honestly, I have both the Daystar robe and the Scylla robe and I love being able to get a cure off in time rather than after the tank or DPS is dead. People play WHM differently but it doesn't have to be a cure beast with the sacrifice of being slow as dirt even with food.