I was actually unaware of St. Denis Church and I think it is fascinating that this was where Gothic structures and design was introduced.   I was also fascinated with the symbolism that you had mentioned between God and light and how it "identified the lux nova (“new light”) of the Gothic church as the symbolic equivalent of God and the windows as mediators of God’s love."  I believe that this is a great reason why it should be preserved because of the importance of the symbolism of the structures and the stained glass windows.  This had provided a message to people of its time and can send a historical and cultural message to the people in the future.  

What do you think would be the closest Gothic cathedral similar to St. Denis today with more modern use of architectural style?