I actually like Cavill as Superman. I just wish he'd been given scripts that allowed him to be Superman. These new DC films have been killed by the writers then buried by the directors with the studio helping pat down the grave dirt. These characters have certain characteristics that are universally recognized by hardcore and casual fans alike. If you don't get them right, then the quality of the story doesn't matter--you've already failed.
I agree he could have been better under a different director, and a better script that actually had a clue about who the character is, but it is what it is at this point. Three movies all ranging from mediocre at best, to just plain terrible at worst with box office returns that also failed to meet expectations. MOS, while it's numbers were decent, didn't do as well as it could have. BvS, again, not terrible numbers, but that was mostly helped by the novelty of Batman, and Superman appearing in a film together for the first time. If the movie was anywhere near halfway decent it would have cracked a billion easily. Lastly, there's JL... The box office returns for that are not decent, or respectable in any way, shape or form. It's laughable how poorly that movie did. Granted, another solo movie with Cavill likely wouldn't be the disaster JL was, but really, how much of an improvement can there really be when it comes to the box office? It just doesn't feel like there's much room for a lot of growth going forward.
Add all that stuff up, and again, I just don't see how it makes any sense to to bring Cavill back. IMO his Superman just hasn't left any kind of impression on general audiences, and if it did, it was for all the wrong reasons like snapping Zod's neck, "Save Martha!" or his ridiculous CGI upper lip in JL. In ten years when people talk about his Superman, those are the things he's going to be remembered for. It's unfortunate because he seems like a good guy, who's a great ambassador for the character, but so was Brandon Routh back in the day, and we all know what happened there.
One last thing with Cavill is how many more movies does he realistically have left in him, anyway? Anything more then two doesn't feel very realistic. I guess he could do more then that, but if it is only one, or two I just don't see the point in continuing. Especially if the other movies end up being guest appearances in Shazam or Flashpoint. I've had enough of this shared universe crap. WB tried, and they failed. Go back to what works. Batman Begins, The Dark Knight, The Dark Knight Rises, and Wonder Woman. All good movies that either flat out existed in their own universe, or had very little to do with the expanded universe in the case of Wonder Woman. Hell, you could even throw MOS on that list. I don't think it's particularly good, but it's by far the best of the three films Cavill has been in, and a big part of that is the fact that it wasn't part of some half-assed shared universe. Leave that **** to Marvel.