They don't sell a patch, they sell a upgrade. The price is imho ok.
Check feature list:
Q: What new features does the Flaming Cliffs 2.0 upgrade add?
A: The following features are added:
- Runs under DirectX 9C
- Improved Mission Editor with trigger system
- New terrain area to include much of Georgia. This will be same map as used in DCS: Blacks Shark. As such the Crimea has been replaced with the addition of Georgia.
- More detailed terrain to include more ground objects, larger forests, and higher resolution elevation data
- Improved clouds
- High resolution airfield textures
- Improved multiplayer system with embedded game browser
- More robust online cheating prevention
- New and improved menu system
- Numerous new, highly detailed ground units including infantry
- Improved flight performance for player-controlled aircraft
- Improved flight models for all artificial intelligence (AI) controlled aircraft
- New, more realistic G-tolerance modeling
- Limited 6 DOF cockpits that move up, down and sideways according to maneuvering
- New and highly-detailed Su-25 model
- Advanced ballistics are implemented for all flyable aircraft, including ricochets of AP rounds
- F-15C locked target IFF indication
- More realistic ranges, seeker guidance and fuzes for air-to-air missiles
- More realistic electronic countermeasure operation and performance
- New and improved sound engine
- New radio message voice-overs
- Random AI look-down clutter notch variable according to skill level
- Adjusted chaff rejection
- Can start inside aircraft shelters now
Most of them are from the DCS engine switch, but there are some completely new features like the sound engine.