OK then. Her’s a list of things in Nuendo, that is NOT in Cubase:
Feature comparison - C7 vs N6
- ADR-Taker Tool
- 64Bit support for Blackmagic and Decklink video cards
- new codecs
- AAF-exchange
- nice Pro Tools compatibility
- bounce-to-markerpoints
- clip-packages/groups
- enhanced automation system
- automation flexible passes technology
- direct stem routing/mixer
- Wave Meters
- Monitor Matrix
- additional post-production plugins, e.g. Nuendo post filter
- PitchDriver, realtime pitch plugin
- MXF audio support
- enhanced EuCon support
- EDL List im/export
- enhanced scrubbing engine
- complete network integration via LAN, WAN
- export Note pad data
- enhanced surround panner V5
- surround matrix decoder/encoder
- additional postpro IRs for REVerence
- enhanced crossfade editor…
- Multiple marker-tracks
- Two video tracks
- Batch Export/Multiple stems export by cycle markers with advanced naming
- Proper Edit mode
- Anymix Pro Surround Panner with upmix/downmix
- Video pull up/down
- Video overlay for text
- Auro 3D format support / up to 13.2 surround support
- Support for IOSONO SAW / Wavefield synthesis products
- ProSoundEffects 1.5 GB FX post-production library included
- extended synchronization/machine control options / Syncstation connection
- EBU-compliant measurement with Loudness Track
- more exclusives coming with Nuendo 6.5:
- BASS management
- AAF 2.0
- … more to be added…
For the Pro Post Studio, many things are doing the price difference unimportant. If they need it, the buy it (and the clients pay for it 
).
As one who has used both Cubase and Nuendo since SX1 and N1.6, I can for the first time see very clearly the bounderies between their Music app and Post app.
Finally has Steinberg’s nagging about the “two different apps” come through to many users, with the difference between Cubase 7.5 and the upcoming Nuendo 6.5.
As a music only producer, the choice of going Cubase only is for the first time easy.
Because I don’t like certain parts of Cubase 7/7.5 and Nuendo 6, Nuendo 5.5 will be my last version.
If Cubase 8 will “fix and/or change” the things nagging me, I will go Cubase only.
But yes there are many things in Nuendo that justifies the price difference, if…if you run a pro Post Studio. For pro Music studio’s only (and/or hobby), Cubase is the way.
Finally I agree with Steinbergs statement on differentiating the two apps. Not so clearly in earlier versions.