Aah, too much black indeed but I saw pictures from another angle (the pic I had seen was from the side so it looked all dark and almost gloomy even though Kate was smiling) and the front panel definitely looks quite sheer. And upon closer inspection, I did see cleavage, too!
I'll take back my previous post, after seeing those other pictures (I thought it was weird that I had such a different opinion) . She does look lovely, but I guess the dark hat was a little too much.
(I did, however, see a video about said wedding, and watched an interview of them after announcing their engagement, and noticed two things : 1) They are definitely lovely and I wish them the best and 2) I really should brush up my UK English skills, it was pretty hard understanding them