Smaller guys can have a believable chance against a larger wrestler if they have some sort of special skill. Like Mysterio's high flying or Bryan's submission moves.
I sort of agree. Smaller guys have to be twice as better as taller/stronger guys to stand a chance. However, I think even then it's a barrier. Mysterio gets a lot of criticism, admittedly from myself too, for being unrealistic and making it difficult to suspend disbelief. A lot of his moves for example, are like bally dancing with his opponent putting effort into the moves. And he is only a 1 time world champion which was forgettable.
I also dont think you can compare somebody who is below the average hight with brackets of those who are well above. For example:
bracket A 5ft '8---- 5ft '12
bracket B 6ft '5----- 6ft '9
You could say that the guy who is 6ft 5 is equally disadvantaged as the guy who is 5ft 8 because they are both 4 inches shorter than their counter part. However, the average height for a male in the western world is 5ft 10. In short bracket B isn't as significant as bracket A. If you are significantly shorter than the average height of 5ft 10 or only slightly above that, then you are signifiantly disadvantaged than somebody who moans about being 6ft 5 because his counter part is 6ft 9.
Sorry for the hypertherical but I think it is important to not treat height differences as all the same because bracket A, aka the shorter guys, are more disadvantaged than the tall guy who just isn't quite as tall as the giant.