we can make mass surveillance much more difficult.
That's true if you made smarter people using the devices that connect to any old open wifi which can easily decrypt SSL using man-in-the-middle attacks. The problem with mobile is due to the smaller interface there's a lot less data available and some things easily spotted and avoided on a desktop have no mobile equivalents so it's easier to be victimized and not know it until it's too late.
Also, while security is great the places already suffering bandwidth issues will feel it just a little more.
All the pings, notifications, pre-fetches and more and more, now using SSL, may look fantastic from a normal broadband connection but you get some sluggish DSL, overloaded or fringe 3G connection, or worse yet the massively overloaded airport wifi and this extra load helps push it over the edge.
P.S. Isn't this a hoot, WP goes "secure" the same day "secure" has a vulnerability, the irony of WP security (oxymoron) just cracks me up: