I think her earl
I know the severity of her style isn't to everyone's taste but she was extremely beautiful in her youth:

I think that the 'softer' hair styles and fashions of the Edwardian/1910s complimented her own harsher, more angular features. (there are some stunning earlier photos of her - helps that she is
really smiling in them - not the smirk of later years)
Obviously this goes against majority (informed!) opinion and conventional wisdom, but I don't think her jewels (gorgeous in themselves) flattered her or that she wore them well.
Jewels (by their own nature - and in their function as a statement of authority and power) are so hard and cold. When I come across a picture of a royal blinged out and think "she is working that tiara(etc)" the common theme is that that individual exudes something inviting/softer/more human - a counterpoint or point of contrast to the gems themselves.
All I ever think when I see Wallis' photos is "OMG can you believe that brooch/necklace" whatever.
She lacks magic.