Headline with a teaser and read more link works better on a mobile device which more people are using for email (I use both but with all the travel this year for work I'm doing it much more on the phone than a regular computer). If the article is short then include it all - just have to figure out what "short" means but I would go with a paragraph or two if the paragraphs only have a few sentences.
I do like the highlights section too - quick and easy to see what I might want to read now vs later.
Good idea here! These days I also use my phone more often than a large screen computer.