Erm, frozen meteorite? Wha? I have a different theory:
*Cresselia is born of dreams and Darkrai of nightmares. I reckon jirachi could make both come true
*It grants peoples wishes, it doesnt say they are necersarrily nice wishes (Eg kill my step-dad :P), presented through doom desire
*I think that he is somehow connected to cressy and darkrai
Orrrrrrrr:
*Jirachi is linked to the beings of will, emotion and knowledge. The elf of desire could quite easily be related to the other 3. On top of that, look at the sprites: They all have two tails, their bodies are similar shades of gray, amd they are generally the same shape (Except the head, which is different on all 4).
Thats my two-pence, let me know what you think. Very little is known about jirachi, so there are no solid theories.