And then there were three.

With Wednesday’s departure of The Dreadlocked One, who announced in advance he was ready to return to North Texas, the 7th season of America’s favorite singing contest is down to cool rocker David Cook, teen ‘throb David Archuleta and the increasingly feisty R&B songstress Syesha Mercado. Cook should and I think will win, and for some of the same reasons Castro had to go.

David Cook

Unlike the purely big-voiced singing that’s been mandatory to success on American Idol in the past, this season saw the emergence of a subtler aesthetic. Castro epitomized it, refusing to reach for the rafters, probably because he couldn’t. He did well on his first Neil Diamond song last week, but from “September Morn” to his Bob Marley and Bob Dylan covers Tuesday he proved you can’t get by on charisma alone.

Syesha Mercado

Cook also has refrained from turning everything into a Whitney Houston imitation. Like Castro, he’s more of an stylist. The difference is, Cook has powerful pipes to call on when he needs to. The shift in the kind of singers Idol is attracting can be traced to last season’s convention-defying Blake Lewis, who finished second, and to a new rule that allows the performers to play an instrument. Since the competition got down to five finalists, Mercado has been the only one not accompanying herself.

David Archuleta