There was a recent announcement in May 2014 that probably went by with not as much fanfare as some of the recent OneDrive for Business announcements. The announcement I am referring to is changing Outlook Connectivity to be MAPI over HTTP - http://blogs.technet.com/b/exchange/archive/2014/05/09/outlook-connectivity-with-mapi-over-http.aspx.
If you check out the public roadmap site, as of my writing today (June 2014), this feature is currently under the Rolling Out phase - http://office.microsoft.com/en-us/products/office-365-roadmap-FX104343353.aspx.
This change is part of the Exchange 2013 SP1 and Outlook 2013 SP1 updates.
So why am I excited?
Up to now, Outlook has used RPC over HTTP (commonly referred to Outlook Anywhere). This change removes the many of the complexities associated to Outlook Anywhere dependency on legacy RPC. This changes the connection to be a true HTTP connection and no longer requires long-lived TCP connections. This ultimately will provide better performance which is explained in detailed in the reference above.
Additionally this change provides the first step for Outlook to natively support third-party multi-factor solutions (such as smartcards). Today third-party multi-factor solutions can be supported with OWA through ADFS. The goal is to support this not just through browser but rich clients such as well as described here - http://blogs.office.com/2014/02/10/multi-factor-authentication-for-office-365/.