That's your choice to enter into lower level content. If you don't like having your abilities stripped away, stick to level cap content. Problem solved.
I hope you realize that means getting new content even less often than we already do. They would have to rework every single dungeon every expansion for the new level cap.
It's much better to leave the system as is. If you don't want to be scaled down, don't do the low level content. Do level 90 content instead.