1.  Home Theater pass-through
2.  Remote controlled source selection
3.  Balanced and single ended connectors for each input and output
4.  Drop the separate power supply
5.  Line level output for the BHA-1
6.  Target price < $5000
1.a With 12 volt HT bypass trigger that works when BP27 is in standby
7.   More detailed volume control
8.   A digital readout for the volume setting.
9.   Remote controlled power
10. RS-232 or IR input 
11. All 12 volt triggers should use the much more common mini-jack
Would also like to see:
a. Modular DAC card that is at least dealer upgradable. i.e. two AES inputs, 1 AES 2 coax, 2 coax 2 digital.
b. Input trim