I've been pulling really old books off my shelf to re-read-- I've picked several by Judith McNaught that I hadn't read in probably 20 years. I wanted to see how the longer romances were put together (I've been writing short for a long time.)
Some things I noted--
--If enough things happen to the main characters, before the romance is resolved, 700 pages aren't always too many even without subplots.
--Using real-life famous people will really and truly make your story seem outdated in a few years.
Overall, though, I still enjoy her long and emotional stories.