I say that the technical merits are irrelevant because I don't believe that they're a major factor any more in most people moving or not moving to Wayland.
With only a slight amount of generalization, none of these people will be moved by Wayland's technical merits. The energetic people who could be persuaded by technical merits to go through switching desktop environments or in some cases replacing hardware (or accepting limited features) have mostly moved to Wayland already. The people who remain on X are there either because they don't want to rebuild their desktop environment, they don't want to do without features and performance they currently have, or their Linux distribution doesn't think their desktop should switch to Wayland yet.
The ability to have multiple displays at different scales is a godsend when trying to use a laptop with a 4k display connected to 1080p monitors or vice versa
I just passed scale to xrandr after computing the proper scale and then used the nvidia-settings gui to write current configuration to xorg.conf its not incredibly hard basically all you are doing is scaling lower DPI items up to the same resolution as your highest dpi item and letting it scale down the correct physical size. For instance if you have 27' monitors that are 4K and 1080p you just scale the 1080 ones by 2 if you have a 4k 27 and a 1080 24" its closer to 1.75. The correct ratio can be found with your favorite calculator app.
You can set this scaling directly in nvidia-settings come to think of it where you set viewport in and viewport out.
Without the recently added wp-fractional-scale-v1, yes, it will do that if you use fractional scales (albeit per window rather than per monitor). Not however if you stick to integer scales, as they might do in the 1080p+4k use case.
Would you not say the best case scenario is for it to just work great straight away and not require you to read a manual or do any debugging at all just to configure your display scale?
Also sway/i3 aren't known to be "it just works" kinda window managers anyway they're definitely aimed at people who like to tinker