My brain for the most part is pretty sweet, just it's got a few little issues. It's like having a Ferrari, you know how hard a Ferrari is to use in actual daily life? But most owners of one would not trade it for a Honda Civic. It's just that you'll have trouble parking it, carrying passengers, etc. Different things have different uses, and I believe God created different people for different purposes as well. I can do things others around me can barely dream about, but then some things that come easily to others come hard to me.
Besides, if I had all that could possibly be lacking in me just randomly given to me one day, it'd be like sorta creating a super human, which isn't fair. I have strengths and weaknesses, it just so happens that my strengths are the general population's weaknesses and my weaknesses happen to be more of the general population's strengths. You can think of it in a yin and yang or whatever kind of perspective, but a population needs to be diverse to balance out things.
Or if you played Fallout 3, just pretend you're a Fallout character, and your INT is X and your CHR is X, and just look at things that way. Most people I know play the game multiple times on different characters, just to see what it's like with different attributes, they all work differently.
And no, you couldn't pay me all the money in the world to get a brain transplant.