Something considered to be extremely lame, disappointing, or undesirable could be described as "weak sauce." The term originates from a technique used in hockey called a sauce shot. A wobbly sauce shot is refered to as "weak sauce," hence the negative connotation.
Weak Good is actually Strong Bad's nemesis. However he is not violent nor homophobic. Weak Good is simply in competition with Strong Bad, but joins him occasionally for a cold one at the stick.