When I hear "youth group" I hear "speed dating for Christians".
Every youth group I've been to made me feel like I was browsing the market. I'd show up and the guys would play with the girls, we'd talk about God- and it was time to FIND YOUR MATE! DING DING DING! Sit next to that girl and talk about the thorny hard parts of your life! Talk to that boy about how you're twenty-something and you're okay with being single for the rest of your life if God wants you to (bonus points if you add, "Maybe he wants me to be a missionary")!
But on a serious note, I've talked to my mother who was saved at the age of 23 and when she went to her churches single's group she said she never even thought about dating in her group. They did things together, including taking a trip to Israel and Egypt, but ultimately the group was learning about God. Her being a new Christian meant she wasn't going to waste a Friday night goofing off. She wanted to learn the Bible and what God expected out of her.
I think that youth group would be more successful if it didn't resemble strangers being thrown together to socialize. You have to think everyone has better, more fun friends outside of church so of course they won't come to youth group for the people. People have to want to come because God is there.
Just my personal observation...