This comment late in the article is refreshingly positive about Microsoft.  Its a positive step that they are suggesting a break from old methods that date back many years. 

I have sat through requirements sessions that listened to people indicating a need to retain access to Microsoft Mail files.  Folks … time to cut the cord.  The corporate costs are in the billions, when you factor in what Microsoft must do to maintain backward compatibility, not to mention the gyrations your Bank must go through, its just not worth it.  Save those old emails as text for legal storage, and move on.

In the long run, she said the company is “definitely investigating” whether to re-architect Outlook’s use of .PST files for local storage, as some users have requested. But she also warned that users shouldn’t view their active .PST file as long-term storage for e-mail.

“Outlook wasn’t designed to be a file dump, it was meant to be a communications tool,” she said. “There is that fine line, but we don’t necessarily want to optimize the software for people that store their e-mail in the same .PST file for ten years.”

Source: Microsoft addresses speed issues in Outlook update