Of course, Microsoft had their reasons for doing it, inconvenient though it might be. However, it amounts to a step backwards in terms of CSS (define) support. We recently had to deal with this issue at our office, and it’s no fun.
According to Campaign Monitor:
Using tables for layout is a dying art in the web design community, in fact many designers who have started CSS/XHTML in the last few years have never even coded a table based layout before. This is a good thing. CSS based emails are more lightweight, much more accessible to those with disabilities and because content is separated from presentation, much easier to dumb down for those reading email on mobile devices. This change by Microsoft means that for at least the next 5 years any designer not familiar with table based layouts will need to learn a completely different way of creating a HTML page if they want to send emails to an Outlook user.
Be sure to download the full PDF guide from Campaign Monitor for all email client support. I guess no one from the Outlook team took time to understand why tables for layout is stupid. Instead, Microsoft kindly gave us all this Outlook HTML and CSS validator.
Will this impact your email marketing?