If "some" of the tourney players and people who play fighting games regularly are having problem with DS's zoning, imagine someone new to the genre. Cyrax and Kabal were a handful to deal with in MK9, but for them to be effective they required a good amount of execution. While DS is not broken, to execute his "gun" moves are relatively simple. This will cause a lot of frustration when a majority of players can do it with ease. Don't get me wrong, it is a legit tactic, but it also means that it created a higher learning curve for the person getting zoned out. The video Tom and Reo posted were great info but I doubt a newcomer can just pick that up on their own. I am just speaking from a casual player's point of view. I will continue supporting Injustice because I like the game, but I can see why DS can be a turn off for a lot of people.
