As someone whose only memory of Ally McBeal is Lucy Liu dripping hot wax on someone (hey, some things stick with a girl), and who hasn't watched any of David E. Kelley's other shows, I don't particularly have opinions on his qualifications to make a Wonder Woman television show. That said, I'm hard pressed to see why, given the critical and commercial success of Smallville, we haven't had more superhero television shows recently.
Actually, it's hard to understand why we haven't had more serious live-action superhero shows at all. Unless I'm missing something, we've only really ever had nine: Batman (1966-1968), Electra Woman and Dyna Girl, The Flash, The Incredible Hulk, Lois & Clark, The Amazing Spider-Man (1977), Superboy, The Tick, and now Smallville. Theoretically, we'll get The Cape as a midseason replacement for something cancelled this season, too.
But superhero stories are, in their origins, inherently episodic. They are our modern serial novels, our cliff-hangers. They're meant to be read separately, sweated over, the collected and devoured all over again. Their abridgment into movies is unnatural, a corruption, even if a very financially successful, and sometimes critically successful, transfiguration. I understand that special effects are expensive, but I do think you'd bring down costs by reusing costumes and sets and amortizing costs over a period of time. And the thing is, what's interesting about superheroes isn't just the single fight with the bad guy. It's how you live with being different, day in and day out. It's why the Superhuman Law arc of She-Hulk is so awesome: how do you live sexually, professionally, and personally when you can switch your personality and your body on and off? Ditto for Wonder Woman. I think to a certain extent, this is a particularly female concern with lived experience. But I think it makes sense for superheroes to return to serial formats, too. Hopefully Kelley will do a nice job with this foray so others will follow.