I prefer a church wedding, DD wants an outdoor cermony, I would appreciate any drawbacks, mishaps or other information that we may not be considering with an outdoor ceremony
Well, obviously, weather is the biggest IF, although you may be in a reliable climate or have a good indoor option in case of rain or cold. Consider whether there will be noise from anything nearby (including a major street). If there is only grass, high heels can be a nuisance.
But I notice that you are asking only for the downside of outdoor weddings, not the upside, or the downside of indoor ones. Are you seeking information or ammunition? :-) Doesn't matter -- we're happy to provide either!
Can you compromise somehow? For example, does your church have a pretty outdoor area you can use? If he has his heart set on a different setting, like a favorite park or something, what can you bring to give it the most important elements of your church? (Assuming that your preference for the church wedding is for religious or traditional reasons, not just its architecture). Or maybe if it's not your specific church that's at issue, you could find an outdoor chapel somewhere, like at a retreat center. Wouldn't that be gorgeous? I have been to several weddings that had the ceremony outdoors and the reception indoors. They were all very nice, UNLESS we were standing through the whole thing. If you are outdoors, please take pity on your guests and provide some sort of seating, unless it is a VERY short ceremony.