What's so wrong with meteorites? I want this spell on my server so I leave a suggestion so maybe someone can make it for me?
Stop calling it spells.
You obviously don't know what the story behind bending is. Bending is not magic. I'll try to explain it to you.
Benders can bend their element with chi. Chi is something that flows through your body (not like blood). When it doesn't flow, you are not able to bend. Now this is why meteorbending doesn't make sense:
1. An earthbender doesn't randomly summon earth to shoot, they manipulate existing earth. They can't randomly summon a comet.
2. Due to fact 1, they would have to get one from outer space, which is simply out of range.
3. If they WOULD be able to get one from outer space, it would take quite some time to get it down to earth.
4. It's simply to big and too heavy for an earthbender to hold.
The best alternative I can give you is to use earthsmash.