With the nature keyword, the illusion keyword, and summoning cards like druid, scepter of summoning, mysterious egg, etc., getting a rare to fuel your legends is super-easy. But yeah, I do think legends are overpowered. On the other hand, I think the cost of other facility-increasing cards is a bit too high. In this case, you have a rare card where the cost per facility is MORE than the cost per facility of uncommons (and I don't just mean legends, I'm talking about cards like quarry, apprentice, curse etc.).
Compare this card to tubular bells. It's strictly worse! There is pretty much no situation imaginable where tubular bells isn't better than this card (ignoring some very specific corner cases, like your opponent having mediator or something).