Due to several circumstances like work, school and other more private stuff I have had to adjust my playing style about two times every expansion.
If I wanted to do the minimal then the game offered me lots of 'simple' stuff to do.
And if I wanted to really dive into the story then the game allowed me to do that.
Did you know that almost every non-combat pet has had flavor-text added?
And have you read every lore scroll that Pandaria has, or did you just click it for the achievement like most people did?
There are also a lot of grey items added with flavor-text and even some talents have text added.
All of them is, imo, more effort at exploration than adding one small line of text to a few weapons.
I believe that there is enough exploration to be found for players who are actually trying to find this exploration.