Now there's no way to get an actual paragraph break in the HTML. Both enter and shift-enter now generate hard break (br) codes.
In practice, two brs is nigh on identical to one close p open p, but it might affect styling is any user tries to apply, perhaps.
Personally I was reasonably happy with the old behaviour - I want a clear separation between paragraphs, and it saves me hitting enter twice, but if others want breaks I'm okay with that.