For future users. You can change the falling friction inside the character blueprint. Select the MovementComponent and look for Falling Lateral Friction. The default is 0
If you only want to reduce the falling friction when using the Launch Character function, you can set the new Falling Friction for desired time then return to normal by putting the MovementComponent then access Falling Lateral Friction, set the value and then return it to default.
I do not recommend the Launch Character for an advanced project like Gears of War or Dark Souls , you have less control. What if i want the character to roll and cover if there is a wall close? or roll and sweep enemy leg all in one movement. A CapsuleTrace would be better and then add the mechanics according to your game.
Hope I helped someone 