'Neutral', compared to what? That's like people saying they want their system to be 'accurate'.

There's no way anyone wants hearing fatigue after a long day of mixing- it sometimes takes days to recover and that costs money if they can't work or are impaired.

I think the Genelec and Dynaudio are pretty easy to listen to- the B&W, JBL and Yamaha weren't. Some of the KRK, Audex and M-Audio are decent, too.

Personally, I don't want some instruments to be reproduced with total accuracy- drums & cymbals, electric guitars and many others are not pleasant to be near, but they can record extremely well. It's the mics, effects, mixing & mastering that make great-sounding recordings. A great audio system makes it sound the way it was intended, or not- some 'great' speaker sound fine for some types of music and some instruments, but some sound really good for a wider variety.