That sounds a little on the lucky side. 1 drop every 200 runs is better than I've seen. It's a free spell drop, of course it's very rare. I got about a spell a week up until I had 12 of 14 spells. Since I only have Samoorai and Deer Knight missing, it's been a few weeks of nothing since Krampus. For a five minute battle, the drop rates are pretty fair compared to collecting all the stuff for crafting. I would say my drop rate averaged out more like 1 every 4-500 runs. It gets harder the more spells you have because you can only get a spell once. I know 12 spells, so I can only win a spell if it happens to be one of the 2 I don't have. If it's one of the 12 I have, it would show nothing.