Also conditions trump profile, especially down here. We have a fair number of pretty flat low corner courses, but if the wind comes up, they can be brutal. Walburg looks like wheelsucker heaven, but add a 20 MPH wind and it's a tactical Belg gutterfest.
Other races look hard from an up/down profile like TNB's circuit race, but every up is followed by a long down that brings the group back together.
You won't see it as much in the 3's, but if teams are willing to sacrifice guys then you're in for a hard race regardless. Other wise look for longer climbs, steep climbs, hairpins, and wind.