I thought the same when I got my Nord Stage 3 Compact and sold my Nord Piano 3. However, I've come to miss the Nord Piano simply because I've found that getting a midi controller with a Nice action, durable chasis, DIN midi out , and an internal power supply means spending about the same as I sold my used NP3 for ( Doh!). So for about the same price, having something like a Nord Piano on bottom gives you all of those features plus the option to leave the top board at home if you want a piano action and don't need any of the Organ or Synth sounds.
-Art