Having access to both blink AND a dodge maneuver would be broken in PvP. Besides, the reason that Warlock doesn't have a dodge maneuver is because of their high-range melee attack that also has a bit of tracking to it. Giving them an evade would start to cause problems when you have Warlocks who can close gaps quicker and smack you from a couple feet away before slamming you with a sidearm or shotgun. That, and it's better for the classes to operate differently rather than trying to make them all more similar.