>>96907975
those cards were printed the way they were because of that rule
guess what happens if you change the rule, the next batch of cards printed will all be Ulalek cost cards

those generic 5c slop cards exist because WotC wants them to exist and no amount of rule changes will stop them from existing because WotC is perfectly capable of printing 5c slop that doesn't actually require 5c to cast even with that rule change