Its only been recently that I've paid much attention to what Kate wears for engagements but my first reaction for the floral gown and the somewhat "big" hair is that it was a definite flashback to the 80s. I remember well buying an evening gown that had a very similar "dust ruffle" and actually the more I think about it, the print of that dress very well could have made a very nice bedspread and curtains.
All in all,
I think Kate can pretty much carry off whatever it is that she wears no matter what the engagement. One thing I do like and notice happening quite a bit is that Kate likes to go for a "period" look. 40s, 50s and so on. I thought the blue evening dress kind of put her into the Marilyn Monroe era with the halter top and full billowing skirt.