10-12 'band' PEQ is the clincher for me.
A "line-in". USB "digital out". True balanced out, XLR and/or TRS.
1or 2 Subwoofer outs. Adjustable "high pass" in main analog output if possible.
A, but with digital input for external CD transport.
(You can offer a matching CD transport. That would be convenient and look very nice)
Headphone amp + audio out + subwoofer out.
Headphone amp should be "sufficient", at least at DX3pro+ level in SINAD and power.
Companies such as Topping, SMSL, Fosi, WiiM etc have a clear run ahead of them in the amplifier segment: Fosi's success with the v3 and their recently released higher power bridged devices are pointing the way. Topping has broken the barrier for reference grade audio amplification at affordable...