No, it is not about Noble Knights. It is all about balance. I can guarantee that nobody will complain about Noble Knight/Dark Magician/Gouki after Balance is gone.
If it's about balance, where were you before then? It's nothing new. Funny how all this daily whining only started when one deck that is really good almost only uses it for their skill.
People already started to hate balance since a year ago when DM abuses it. Just that DM was not as broken as NK and they have decided to limit DM cards instead of banning balance. At any point of time starting hand manipulation is a can cer.
Dm playstyle was like cheating with balance. However, dm decks needed a turn to set their field and if circle was gone they was an auto loss. On the other hand nk can be explosive in their first turn. Going 1st or 2nd is the same for them.
A good nerf for balance could be "you can't summon any moster in your first turn", just like the nerfing of "duel stand by".
DM still got a lot of play with destiny draw, sealed tombs, born from earth, master of rites, etc. compared to noble knights with balance. So it wasn't as big a thing. Book of moon could be a different story (no pun intended) for balance.