it doesn't matter how good either of those rewards are, if it's gonna take weeks just to get to them, while you could just go for 99 mining with a regular rune pickaxe and it'd still be much faster than getting a dragon pickaxe first and then mining regular rocks second.
I don't think the first intention of crashed stars was for people to get 99 mining there. You're suppose to mine the star between other activities and once you reach a certain amount of dust you'll get a reward for it.
The question remains whether the rewards are worth the time it takes to get them. And based on people commenting here it seems like people do want the rewards.
I'd just reduce the time to 2 hours.