I think all of you who try to define what a miracle can and can not do, are forgetting something.
The DM makes the call.
I lead a game with epic level clerics in the group where miracle-tossing have become the standard routine procedure in each and every other situation.
To evaluate what my players can do I'll have to check on the cleric's relationship with her deity and figure out if she's worth the cake she yelled so frantically for.
If I deem she is, then the reality of the miracle kicks in.
I for one, judge the miracle spell to be the most powerful spell in the whole game. Most lower level spells can be duplicated (no XP charge), and almost anything else can be done for a mere 5.000 XP.
In this way, miracle is clearly superior to wish in every way. Why?, deities can grant stuff mortal beardwearers in woman's clothing can never dream of, and thus by imparting just a slight bit of this godly souvereignity to a epic cleric, that cleric, she can raise one of her abilities* if it fits the story.
*In fact, raising one ability or another, is not that a big deal, really. Far too many of you think of D&D like some off-shot from the CPU (like Diablo) in which slaying monsters actually makes the character better at Profession (gardener), instead of it as a tool (as in tool, not some law to follow to the letter).
So, I think you are jumping on this kid without really thinking about it. He started this topic with his particular statement (which we are free to judge right or wrong by our own standards, of course), and I want to add in something....
He's absolutely right*.
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*But then again so are you (on the subjective level of nonsense-arguing).