If you want to use your original words verbatim, you can use a semicolon to separate the two phrases. "I am bad; love me as I am". While this is grammatically correct, for the purpose of dialogue it doesn't flow well. You could say "I may be bad, but love me as I am", but again, I personally don't think that it's a natural phrase. A better option could be to try phrasing it as a question, such as, "Can't you love me as I am, even though I'm bad/a terrible person?" or, "I may be bad, but can't you love me as I am?"
As for the second question, it is grammatically correct, but I share my precious sentiment about the way it flows. The phrasing is still a tad awkward. A more natural way to say it could be to replace "good" with a more descriptive adjective, such as "righteous" or, if you're looking for a more creative way, "Nice guys might finish last, but everyone still loves them"/"Everyone loves the nice guys".