Because there's no secret formula for making good media, as much as corporate execs wish there was. The creators of this show made a fun character with a personality somewhat different but still recognizable as a younger and less jaded Lois, and a redesign that is drastically different but fits the new personality like a glove.

That's it, in this case.

Yes, certainly. While there are more bad raceswaps than good ones, Nick Fury will always be proof that is not universally bad.