Art is not exactly science and there is a danger zone if one places science as the sole pillar to judge art. Science can be beautiful if one uses it on a positive complimentary mate and not place it as the ultimate authority. For all of you DxO faithful, that include me, I hate some of their numbers as they don't tell you the full picture, let alone confuse one's finding in both cameras and more problems on lens rating. I like the Artsy type of gut feeling with lens test that one takes a single camera, 1 lens and 1 soul and take quality pictures as if there is no tomorrow. Can the power zoom lens do that for me? Hell yes and hell no. It depends what I am shooting. If I am shooting for a competition or a hired gig, hell no as I have better gear. If it is meant for my traveling as well as memory keep-sake that demand the lightweight and compact form factors, hell yes.
Corners look alright to me as there is not much to see in the cornesr. I am enthusiast and not professional though I may shoot more quality pictures with this zoom than someone blindly buy the web findings with good numbers. Screw the numbers! And discern with your personal opinion and judge it with your own eyes and vision. Hell with other people findings, what matter to you is your own liking and it is mostly subjective and perhaps partially objective that can be measured on graph and qualified as number in a curve.
Not a great picture above to show but I want to see the off focus rendering . Corners? What corners as they are all blurred in thinner DOF type of shooting.
Hope I don't inflame the haters of the power zoom. Please agree that everyone don't think alike and I actually like people open and not thinking like myself as we learn from each other like a true friend who tells you honestly right in your face what you don't learn and know otherwise.