We had ours done in a park as well, and we wore jeans... Our wedding is considered formal, but we don't want it to be stuffy, and it just wouldn't of been "us" if we had gotten all dressed up for our engagement pics. I think we had more fun being ourselves. I think that if you want to do casual pics it's fine.. Like I said that's exactly what we did, and I don't regret it, everyone loved them.
