Going to add my 2 cents here on why I agree with Slayer.
Jupiter and REO are obviously great players, they wouldn't have done anything if they weren't, but I can't call them the best. It's like the guy using the All NBA 90's team against the Heat in 2k. Yes the Heat are great, but they aren't the 90's All NBA. If you are both of equal skill more times than not you will lose to the All NBA team because the team gives an extra boost compared to normal NBA teams matched up. Even if you are slightly more skilled you may still lose.
This was vanilla SF4 Sagat. This was pre-patch Tekken 5 Steve. This is MMH.
The only reason why you don't see "8 MMH's in the Top 8" is not because he isn't far superior to the cast, its because many people wouldn't enjoy just dropping their mains or favorite characters just for the retarded one. Many wouldnt want to be hypocrits. Many would rather win their own way. Plenty of reasons dependent on the actual individual. Nevertheless, it doesn't change the characters far superior tools.
For example, if you are losing with MMH it is much worse than if you are losing with Raven. Both are top tier characters, however the gap between MMH and anyone else is very high and will grow even more in the future. Unless you outplay your opponent from beginning to end you will lose with Raven. You can be slightly outplayed using MMH and still win your match because of the tools available.
So no, a character isn't as good as the player, they are as good as they already are made to be. If the player can play at a high level they can maximize the potential of the character. If the players are at equally high levels then a character with such an advantage over others also gives that player advantages that his opponent does not have. As Slayer stated, he virtually outfootsies nearly the entire roster, outzones everyone, can't be zoned by anyone, super safe, high damage, setups, uses little meter, etc etc etcx100.
People need to stop looking at this like its "taking shots" at people and call it out for what it really is. A fact. We should just be fortunate that everyone doesn't play with him because then you actually WOULD see 6 MMH's in Top 8's.