Note that the description of Miracle is not identical to Wish. There are several major differences. First of all, Miracle does not allow for raises to ability scores, creation of magic items, etc. such as Wish does. Miracle is also directly tied to one's god. Better hope that said god is pleased with you, thinks your cause is a good one, and isn't irritated that you're interrupting his divine game of pool. These are some very real drawbacks.
Also, if you wanted to do anything other than mimic spells as listed, you'd run into an XP cost of 5,000 anyway.
In some ways it's nicer than Wish, but in other ways it's not. Don't see a problem with it myself.