The app is user-dependent. It would be the match.com for date planning. People create maps of where they went on a date previously and people can follow that date if they are matched with that person based on their dating needs and criteria (i.e 1st date with a moderate budget. It's more of a convenience tool and saves time from scouring sites like yelp, foursquare, metromix etc.
What can be appified other than the most mundane parts of the date? Planning dinner then a movie is boring and can be done probably better with existing apps.
Only if you're dating a computer. Making a few assumptions (you're a guy and it's a date with a girl), I can't think of anything less encouraging to a woman than to realize the date is running to a schedule.
Take a huge risk -- don't plan the date, experience it.
