"Assuming fully balanced equipment"
That's the key right there. If the equipment (but principally the amp and preamp) has fully balanced circuit topology, then 'yes" balanced is better -- and for all the reasons you mention, and one other very important one you didn't:
You're giving the circuits more (voltage, usually) to work with (resulting in better signal to noise values) and conversely, you are engaging the circuit(s) to their full design capacity (resulting in lower distortion levels.)
So although the advantages you mention are real, they all have to do with the differences between the cables themselves (SE vs. BAL) whereas my focus has more to do with what the equipment can do with a balanced signal vs. a single-ended signal. The reason Steve McCormack said what he did, is that the DNA 500 uses the balanced input "as is" (the amp is a fully balanced design BTW) and has (I presume) alternate input circuits that "convert" SE input signals into balanced form in order to take full advantage of the amp's balanced design. This is a nice feature, but notwithstanding his remarks, I'd feed it (the amp) a balanced signal if I had one available.
That's the key right there. If the equipment (but principally the amp and preamp) has fully balanced circuit topology, then 'yes" balanced is better -- and for all the reasons you mention, and one other very important one you didn't:
You're giving the circuits more (voltage, usually) to work with (resulting in better signal to noise values) and conversely, you are engaging the circuit(s) to their full design capacity (resulting in lower distortion levels.)
So although the advantages you mention are real, they all have to do with the differences between the cables themselves (SE vs. BAL) whereas my focus has more to do with what the equipment can do with a balanced signal vs. a single-ended signal. The reason Steve McCormack said what he did, is that the DNA 500 uses the balanced input "as is" (the amp is a fully balanced design BTW) and has (I presume) alternate input circuits that "convert" SE input signals into balanced form in order to take full advantage of the amp's balanced design. This is a nice feature, but notwithstanding his remarks, I'd feed it (the amp) a balanced signal if I had one available.