Title says it all - from the Destiny blog [url]http://thedestinyblog.com/2014/07/27/report-destiny-will-have-22-story-missions-11-crucible-maps-6-strikes-4-exploration-areas-and-1-raid-at-launch/[/url]
That is far too short if its all of it. The missions aren't very long/challenging for the most part... and strikes aren't really longer unless you have dead weight on the team. However, they do have the disclaimer at the bottom saying its not an official list, nor has it been commented on by officials. So... take it with a grain of salt.