Lock screen layout has always been at the mercy of the Android device manufacturers. It is one of the few pieces of the OS that cannot be customised beyond the background image.
Until v. 7.0 there were two flavours in the lockscreen layout: one with the clock near the top and one with the clock near the bottom, with the clock taking up about 20% of the screen. With Android 7.0, Samsung decided that its users are blind, and the clock digits were not large enough. So they decided to double the size of the clock digits and stacked hours above minutes, taking up about 40% of the default lock screen layout height.
The whole idea is to be credited to Samsung theme design team. We feel we have to congratulate them. Nobody has ever come up with such a ridiculous idea, making the clock barely readable – everyone is used to read clocks from left to right; top to bottom is something unheard of.
This comes with a minor side effect for our Android users. Since any device manufacturer is free to screw up with the lock screen layout, we cannot keep on suggesting to our users replacing their lock screen background with their ScreenTag code image (actually, we could keep the suggestion with the addition of disabling the lockscreen clock, but we cannot ask that much). Thankfully, the home screen offers a lot more customisation options, and thus we shall continue suggesting the replacement of the home screen background image, as an easy access option for our Android users.