I'm looking for general purpose zoom and F4 is perfectly ok with me on FF. I can appreciate and work with that happily. However, I want to optimize lens + body combo. Will this zoom weakness (soft corners) be more apparent or less on 42Mp A7Rii compared to 24Mp A7 and 12Mp A7s(I or II)? It's expensive combo and I want to avoid soft corners as much as possible. Which body can minimize that flaw? I heard different theories: some say 12Mp is best for this lens as any imperfections are less noticeable, others say opposite.

It probably would look best on A7s, followed by A7, followed by A7r. I say "probably" cause I haven't tested this myself, but I have experience with A7s, A7 and A7ii, and I have seen lenses that looked perfect corner to corner on A7s pretty awful on A7 or A7ii.There doesn't seem to be consensus however, some people say that some lenses look better and sharper on high-resolution bodies. Depends on what's the limiting factor, the lens resolution or the sensor resolution and how you value center sharpness versus corner performance.Personally, I would choose the body based on its features and my needs, not on its performance with a particular zoom lens. Hard to imagine that you would be disappointed with any of the bodies.