No balanced inputs..ahi ahi!! my Metronome Cd4 would suffer too much...... 
The reasons behind not offering XLR input:
1) If the XLR output is truly a balanced design, then taking 1/2 the signal does not compromise the sound.
2) Most 'balanced equipment' are simply "bolt on" a phase inverter stage fed from the main, non-inverted, output, to provide the XLR output, as a result, there is a time-shift between the two phases as the inversion circuit inevitably adds a time delay.
3) Typically, cable run from source component to preamp is fairly short.
4) Keep in mind that the sole benefit of using XLR cable is the 'perceived' cancellation of 'hum and noise', but this only applies to AC-induced common mode noise. Balanced connection will not get you lower THD at 10kHz, or provide any improvement in broad-band noise floor. Wide spectral noise are not common mode, and they don't cancel out. The addition of extra circuit also adds more spectral noise.
One way that wouldn't compromise performance is to use a balanced input transformer, and future ultra-high-end Nuforce may incorporate such element.
