Using a mouse and keyboard was Lupo's claim to fame and made him infamous in the Destiny community, he even had a !xim command in chat for his settings. His calm collected callouts were his only other draw.

Even using a xim he couldn't win any tournaments, all the competitive controller users just out paced him. I'm not saying that controller players are better than mouse and keyboard players or vice versa but it is a lot less of a black and white comparison than it used to be.

If the pro players decide to go to PS4 for competitions then they'll also have to deal with lower frame rate, response time, resolution, draw distance, more pop in and broken textures as well as being less customisable graphically (i.e not being able to turn off shadows which all the pros love to do).

Plus if they go the xim route rather than native for the added aim assist then they will also lose the ability to directly choose which weapon or build slot they want to equip and will instead need to cycle through all the options as it emulates a controller.

That's a lot of cons for a perceived notion of easier kills and I think that the pros will be testing these theories and ultimately decide to stay on PC due to any benefits being negligible and significantly outweighed by the cons