I think there is a backlash against X-Ray combos for some reason... but if it wins you the game... I do not understand why people do not use it. Many x-Ray combos can go above 50%.. easy some as high as 80s and some characters like say Mileena or D'vorah are not hugely meter based or like Kotal Khan who can build meter in a blink of an eye.
In a game like MK where it is all about momentum and "his then her turn" I just do not see why closing out the round or the game with a massive combo isn't the norm. Like you can easily loose the game even if they have a small amount of health left. Particularly with 1 touch monsters like Quan or Cyborg.
I think the incorporation of X-Ray into the combos is the next step in the evolution of MKx play... The breaker is important in this game, no doubt, but if they are dead you do not need breaker. I feel that the thinking on this is a little outdated and is a left over from mk9.
I mean the amount of time I have seen some pro player punishing someone in the corner and ending in knock down when Xray would kill... . . I think many games are lost when they shouldn't be if they used this tactic.