We have been trying to get Epic refines added into events, but it is not guaranteed to ever happen. I think it would be a great idea to add them into these events, but it might reduce the amount of sun scrolls obtainable.

Some people are only able to attend events on certain days, so it could make things more challenging for them, but I definitely agree that it would still be a worthwhile trade, but even then, it might not work out to get this implemented.