That combination of a very slim band, usually around 2mm, and small pave diamonds has been a popular look for the last 8-10 years. There's been lots of discussion in jewelry forums about the durability of the rings made in this style, and whether the combination of honking big stones with very fine bands is proportional or not, but the changes to Meghan's engagement ring are certainly in keeping with current jewelry styles. I liked her original ring, and find it interesting that apparently she was longing for a more blingy upgrade just like many other women!
A pave of tiny diamonds is hardly a bling upgrade. At least not the in the sense of upgrading engagement rings.