From my experience, as I said it before, you don't have to tweak anything to have agreat sound from your Korg arranger.
But, because you have a lot of tools to do it and because we all have a different idea of what the perfect sound is, many user will spend time tweaking it and, rightfully, they will emphasize that only NOW their arranger has the perfect sound.
Does it make sense?
Right out of the box the Korg instrument is great, to those who like Korg sounds. But you can make it even better for yourself, by spending time with it.