Many fans are complaining that the Protoss Mothership is way too powerful, while others have started petitions to remove the Mothership from the RTS game.

Drysc has made a clarification of why the Mothership withstands too long in the gameplay trailer:

Drysc: “If you look closely at some of the higher quality versions of the gameplay video you can see that the mothership was set to invincible.  We cheated a little to help show off all of the awesome abilities it has, and allow everyone to get a good look at the unit and the work that went into it.”

You can relax now guys.  The mothership is not extremely hard to destroy.