I agree with almost every thing stated above, except for Number three. If folks want an army of eggs so let them. They can have hatchling armies, why not egg armies?
Also, I do not like the idea of 'piecing them back together" That is not freezing, that is rebuilding it. And as another poster said, it is like having your cake and eating it too. If you freeze a hatchling you can't then turn around and unfreeze it to let it grow up to try and breed or trade it. You made that choice when you froze it and you have to live with consequences of your choice.
The time limit is a good idea, like breeding, influencing or biting, or most of the other BSA's, you should have to wait to freeze another egg. I agree that if you do not, there is a potential for misuse.
The dragon of choice for me to have the freeze action, is the Ice Dragon.
Any egg should be aloud to be frozen. CB or bred, just like hatchlings. Yes I know wome folks get upset when you freeze a 'lineage' dragon, but once you gift it, abandon it or trade it, you have given up the rights to what happens to it. ( You can always make conditions before with the person who is t receive the egg or hatchling. However if you do not, then they can do with it what they want)
Freezing eggs seems fine to me. As stated, the sprites are very pretty and many people would like to have a complete set. Knowing me I would probably for the most part only freeze my own eggs. Though I have frozen many hatchlings that I got from cave born eggs or the AP that no one has claimed.