Well, I have to say this. I guess my forum post was a bit over the top, and I might want to recall I don't support WD anymore.
Today I was called by someone from WD customer service, and they apologized for the bad performance of my NAS.
They offered me the choice to get extra disk space or [edited]
I must say I am impressed. I never expected you guys to even read this message, so great job
I won't buy a new nas from you, but your hdd's are still welcome
Thank you WD for your great customer service!