This reminds me of a guy I played online with good stats (if they matter) who mained Johnny Cage and knew all the tricks.
As usual, I chose my main (Mileena) and pretty much bodied him every match. He then sends me a personal message saying I won because I played a broken character (Ed Boon said it himself) and there is nothing you can do to punish her enhanced telekick. I wasn't sure if this guy was shitting me so I just replied "Dude, are you serious? You play Cage, learn the match-up." Afterwards in the chat room he starts blowing me up saying "only loser play Mileena" bla, bla, bla, so I send him a personal message requesting a "no Mileena challenge" which he accepted and guess what happened..........
In conclusion, there might be characters in Mortal Kombat labelled "overpowered" but in the wrongs hands or against certain individuals they might not be as effective thus making the Top 5 / Match-Up chart obsolete..........in my opinion of course.