There's nothing explicitly wrong with them, and I appreciate the efforts in improving immersion, they just get in my way. That's it.
They hinder my flying and shooting when in cockpit view. The simple, vanilla cockpits were an aid to, for example, quickdocking larger ships in a tradelane. These cockpits occupy too much of my screen and also distract me, but on the other hand, a completely blank one is too little for me as well. That's why I want to restore the old ones.