(2) Just so stories: totally. And one major advance was Williams&Nesse, 1994, why we get sick. The question is not „Why is Depression an adaptation“, the question is „Why did evolution leave us vulnerable to depression“).
There is a good youtube video about that with Dawkins & Nesse.

But: just-so stories have nothing to do with the field itself. Just because people write bad papers about gravity doesn’t make gravity inexistent
(3) Stepwise vs gradual: it is not very smart to think in these categories. There is no reason to assume that this is an EITHER OR question. Because it is not. Antibiotics resistance in bacteria is a good example. Would that be stepwise or gradual? Hard to say, by definition of these words. Both mechanisms clearly exist, and we know that. 
(4) „Whoever wants to claim that science is just progressing on its path of objective truth, with random imperfections that will be smoothed out over time, good luck„
Not random, we have systematic errors, the biggest one being the human being itself with all its biases. Still, we do smooth out things over time.
(5) „The range of social issues he mentions which are justified as „natural“ through the dominant understanding of evolution is broad, from male domination to social hierarchies, aggression and sexual coercion.„
Nobody with a brain does that. I want to see quotes here, from leading researchers in the field. Because I don’t know a single one. When Thornhille&co published their book about rape being an adaptation, they wrote a couple of introductory pages about how this is NOT a moral judgement, how this does NOT mean that it is ok to rape etc.
Newspapers, women’s rights organisation etc just ignored this chapter of the book completely and summarized: Thornhille says rape is good.
(6) ta-ta, E.

Danke für Deine Gedanken.

I very much agree concerning keeping the purpose of evolutionary theory in mind, even though I think it can (!) be fruitful to bring it into other fields, just like almost always bringing concepts from other lines of thinking in is a „creativity technique“.

I don’t quite understand why social science should have to deal with this „lock in“ problem at all. Aren’t social change processes in general thought to be driven by finality (as opposed to causality) — they occur for something as opposed to because of something, and can naturally occur in big lumps — large laws or sets of laws passed together like our upcoming Energy Turn? Or are you referring to more abstract, less formalized norms? Even there, because of the meaning-making process they are part of, I would argue that broad, related changes can quite easily occur together, take the 60s with their famous cultural revolution spanning art, teaching, family values, politics, etc.

A remark concerning „we may not get rid of a meta-principle like ‚fitness‘“: of course we need principles concerning utility, desirability, fitness/„fit“ (in the sense of being appropriate for a specific circumstance, much different from the general implications it has usually taken on!), maybe „correctness“. But the question is which word will be best used for this concept in different concepts, and borrowing the biologically colored concept in social science and even epistemology invites a host of undesired connotations, so we maybe better look for another word. And I think the change of meaning and discussion will not even be very subtle. Like substitution „useful“ for „right“ when talking about theories…

And: Interesting definition of political correctness! Mine (ad hoc) would be: Speaking (writing, etc.) in a way that is aware of the way words and concepts shape how we experience the world and how we will be inclined to work for change in the world — much in line with what I wrote above about the fitness of theories, a wording I would never use (even though I like fit).