Considering they are heavy advocates of modding their game and have already released tools to enable modders to create even better applications...I'm fairly certain there will be a mod that is just like Tera in terms of action combat. I'm not sure if projectiles can miss like in Tera, or if all ranged attacks have templates for aiming, that's all coding and nothing to do with the UI...but I'm sure they can change it to mouse aim for general purposes.
I also expect that if this game becomes popular you will see more and better addons than we have ever seen in an MMO, since they are already planning on being so invested in the process to the point of figuring out ways to reward modders and take their work to implement permanently in the game.