There are several reasons why wingsuiting is considered more dangerous then regular skydiving. Most of the dangers are related to lack of experience.
- Bad exit, hitting the tail.
- Unstable deployments resulting in malfunctions.
- Bad body position resulting in big burble that might Oscillate your pilotchute into another dimension!
- Lazy pilot throw, resulting in pilotchute Oscillation/twists.
- mid air collisions with other wingsuits.
Actually, I've done all of these (except for hitting the aircraft tail).
Except from the problems listed, I think the most dangerous part of wingsuit flying is the deployment. Wingsuits are like straitjackets, you can't make inputs to your canopy during opening. And when your canopy is opened it is extremly important to pay attention to other canopies. How many times havent we seen wingsuit video, then after deployment the jumper starts unzipping and does not pay ANY attention to the airspace. This is not really just for wingsuits, but it is easier to get distracted by all the zippers.