Intelligent Design

[JuliaL]

I don't get why it's either keeping of good genes over bad mutations or good mutations can't have any role. Obviously, for good mutations to work, they have to get kept over time, and since majority of mutations are bad, of course, it's mostly natural selection working for to keep the good genes there. However that is not to say good mutations don't happen.

In what sense are you calling mutations "good" or "bad?"
The only use of these terms in the context of evolution by natural selection is that "better" genes result in more offspring.
This is what is seen universally. 
The products of "worse" genes are less represented in future populations so we don't see them.
By saying "the majority of mutations are bad" you invert the inference to be made from these observations.  Mutations are not eliminated because they are "bad."  We call mutations bad because they are eliminated or good because they are kept.