That's wrong... What they did in SWORD didn't make the WHR just a mysterious place but it made an extremely powerful and relevant place. (moreso than before) They made the WHR and the Mystery the same Place (the Above Place like Doom said). If you have read other comics that's pretty powerful because the Mystery is a Realm outside the Multiverse/Multi Eternity. Also, the WHR is the Heart of the Phoenix and the mindscape of the Phoenix. Its the Phoenix in its purest form. Only Teen Jean and White Phoenix Of the Crown Jean as the True Phoenix have been shown to manipulate the power of the WHR.
Also the titles Elemental Cosmic Heart, Excelso Prae Omnibus Aliis,Mysterium Tremendum, The Mystery, White-Hot Room of Secret Fire given in SWORD are all for the same place the WHR. They are just different names.