When I run a 10k, all I really want is a real 10k with people to race against. That's it. I've run one really massive 8k (20,000+ people) multiple times that's a blast and is a bit more expensive ($35 I think) but it's also some of the best road competition I've had in my entire life, it really supports local elite runners with some big cash prizes (note: I'll never place in this race, as it's routinely won by pros), it's a major community event, and it's insanely well-organized. It has 52 starting corrals, starting at sub-29 pace all the way up to slow walking pace.
So I'm willing to fit the bill a bit more for an event like that. But frankly, if that race didn't do such a good job ensuring that it's a good competition for somewhat faster runners, I wouldn't run it.