Mediocre and average are synonyms of each other. Contrary to how people use mediocre on TYM, the correct meaning isn't bad, but average, middle of the road etc more or less.
Specifically, Mediocre means being of just barely passable quality (70 would be a mediocre grade, whereas 75 would be "average"), it doesn't necessarily mean the same thing as average but the terms are interchangable, but only for the absolute bottom of what qualifies for average. So saying Kitana's zoning is "average at best" does not necessarily qualify it as "mediocre" as one doesn't necessarily draw from that statement that her zoning is on the brink of unviability.
Mediocre would be something one would use to describe Ferra/Torr zoning, wherein it serves its purpose and can be considered "zoning", but if it were even slightly worse or put into a situation where any situation works against it (projectiles that can't be eaten, for example) then it would stop being a viable option. Whereas if Kitana were to struggle with zoning, she could still zone and reap SOME result, but not as good of a result as someone whose kit fits a more universal situation.
Average > Mediocre, but the bottom of Average and the top of Mediocre are in the same spot.
