I can't remember now where I saw it mentioned -- here or on S-G? -- that the Beta version of the cleric lets him actually turn undead as opposed to, y'know, not being able to do that thing. Which is an improvement!
That said, I'm a little bothered by the new form it's taken. "A number of mindless undead equal to your level" seems to really hamstring the cleric and prevent the classic turn-the-vampire-with-your-holy-symbol trope. However, without monster levels, it's not so easy to quickly differentiate between various gradations of undead without GM fiat ("Well, no, the vampire lord obviously isn't turned, no, but those skeletons, yeah, they cower and back off").
What about using the one defensive monster stat that still remains -- Hit Points -- as the basis for accomplishing something like this? It seems like doing this could also recall how Turn Undead works in AD&D, too.
When you hold forth your holy symbol in a show of faith, roll+Cha. Compare the Hit Point total of every nearby undead being to the total of your roll. If an undead's HP total is less than your roll, the undead is destroyed. If an undead's HP total is greater than your roll but less than twice your roll, it cowers at your power. If an undead's HP total is twice your roll or greater, it is unaffected.
Now, look. I know I like rolling dice, and tend to insert dice-rolling into DW in places where maybe other people wouldn't like it. But this strikes me as consistent with the core mechanic and more fun than the guaranteed certainty of number = level. And you get to make skeletons explode just by shouting at them.