Many people feel cloning dogs is wicked, or at least potentially wicked, because "if it were meant to be, God would have done it."
I can think of many reasons not to clone dogs, such as the millions of perfectly fine, good, true, loyal dogs that are put to death every year, and the creepiness of trying to repeat a relationship with a new dog that you had with an old dog. And cloning is risky biologically: how do you think we got the Irish potato famine? The whole evolutionary point of sex, the reason all but the most primitive species go to all that trouble, is probably to psych out the microbes. Cloning defeats that.
But the "God would have done it" argument falls flat with me. If God had wanted us to fly, He would have given us brains to design flying machines with. Oh, wait. He did...
[And, to get all more-Judeo-Christian-than-thou about it for a moment: in Genesis 1:28, God commands us to "be fruitful and multiply." Seems like a go-ahead to me, there, buddy.]