That makes things a lot harder for editors of the less prestigious journals, and that's why I am more inclined to take on reviews from them.
I would not want to review for a journal that does not offer an unbiased review process.
Do the hypotheses follow logically from previous work? To what extent does the Discussion place the findings in a wider context and achieve a balance between interpretation and useful speculation versus tedious waffling? (Then, throughout, if what I am reading is only partly comprehensible, I do not spend a lot of energy trying to make sense of it, but in my review I will relay the ambiguities to the author.) I should also have a good idea of the hypothesis and context within the first few pages, and it matters whether the hypothesis makes sense or is interesting. I do not focus so much on the statistics—a quality journal should have professional statistics review for any accepted manuscript—but I consider all the other logistics of study design where it’s easy to hide a fatal flaw.
Mostly I am concerned with credibility: Could this methodology have answered their question?
I do this because editors might have a harder time landing reviewers for these papers too, and because people who aren't deeply connected into our research community also deserve quality feedback.
Finally, I am more inclined to review for journals with double-blind reviewing practices and journals that are run by academic societies, because those are both things that I want to support and encourage.