A Chord Sequencer....

76 notes
Ballsy Bass and Drums
Better piano (warmer, more Steinway-ish)
Better organs (more grind!)
MUCH faster sample loading and saving
AKAI multisample import
Better MIDI for external Parts, and better MIDI function control (for slaving two arrangers together)
Motorized faders (no up/down buttons. How can you hate Nord but like the Yamaha's?)
Virtual Analog Synth, with knobs!
Ability to play MotifXS patterns, but with Arranger control.

I guarantee that the T3 will have NONE of the above!