My list so far. I'm sure a lot of these will fade in time (hopefully).
- Sanctuary
- AMS's
- Lack of classes/old certification system
- Advanced Hacking
- PS1 style bases (and especially base walls)
- PS1 vehicles and their difficulty to take out as infantry
- Lack of too many lock-on weapons
- Vehicle enter/exit animations
- Lots of health
- Subscription fee
Edit:
New ideas that I like:
- Jet packs
- More spawn places
- Gun sights
- Improved combat
- New flight mechanics
- Customization
- Improved graphics
- Night/day cycle and reintroduction of weather