The semi-mythological elements weren't necessarily the best, but we always knew something like this was on the way, to explain Clara. I think it was less confusingly bizarre than it could have been, and it had Madam Vastra, Jenny and Strax in it, so it can't be all bad! The way they've left things we probably can't expect then to be in the next episode, which is a shame, but I'm sure they'll be back, because they always produce a good episode (even if this one was a bit weak).