I agree with you. They should show off more sounds than just the pianos (even though the pianos are extremely good on the Nord Stage line). There is ALOT of differences between Nord Stage 2 and 4. If the upgrade is worth the money is entirely up to you. But here is some very important upgrades: - New and improved triple sensor keyed, Drawbars on the organ (some people like the old digital drawbars aswell), The synth engine is night and day better than the Stage 2, a lot more (and better)FXs, Every single layer can now have their own FX layer (they don't need to only be global), Every layer can now be easily routed to external midi keyboards (imagine the possibilities in a band situation, were you can in ex. route the synth-lead to an external midi keyboard and have another band member play the lead, while you are playing chords and bass on the Nord), poly-arpeggiator (which can be customized), B3 Bass Organ, The Stage 4 also has the improved C2D organ engine (which the Stage 2 doesn't).....and much more.