If The Wire had stopped at the end of series 4, then yes I'd definitely agree. But it didn't.
It's a tribute to The Shield, and I suppose it's a possible side effect of the kind of show that it was, that it was no less riveting despite the departure of its most sympathetic character in series 5. But, like The Wire, I think it's strength was, well, the writing obviously, but a whole cast of characters that kept you entertained and engaged whether or not Vic Mackey was on screen. And that puts it ever so slightly ahead of the Sopranos for me- the first part of series 6 was an interminable drag as far as I was concerned.
