A lot of the time moves in Tekken are calculated on their ability to be punished (ie. how open the character is once they're blocked.) There are a few moves in the game that are simply unpunishable, due to circumstances here and there (knockback, duration of knockback, knockback animations control player for too long, etc) and noob players will often abuse them with unfortunately good results.
The penalty system I suggested would be similar to the N64 Smash Bros version, where the use of the same pattern of moves for lengthy periods of time would incur penalties of G (like in Smash Bros, you get docked a certain amount of points as per Cheap Shot). Yeah, it's definitely a reasonable point that predictable players can be beaten when repeating moves, but there are moves out there that not only cannot be countered very much afterwards, but ultimately only slow the game down to a turtling match.
And in Smash Bros the penalties were only enough to chip a bit off your points. Likewise, it could have just been used to slow down the amount of G you gather in game.
EDIT: Kunimitsu was a royal bitch.