This is something worth pointing out - the Essentials doesn't change  anything that you like about 4e.
I don't want to say too much,  since we have more preview articles coming out, but if you decide you  don't like anything in the Essentials you'll still have plenty of new  books, interesting options, and so forth to look forward to.
To  pull the key sentences from the article:
"If you’re already  playing a Dungeons & Dragons game, there’s  one very  important thing to remember—the Essentials products matter only  as much  as you want them to. We very carefully designed the new classes  and  added more options to the races in such a way that existing  characters  remain unchanged."
It was critically important throughout the  design process to make sure that the above statement was true.