Seems like you don't understand what is an abstraction.
Nope, seems like you're arbitrarily distinguishing between abstractions and lazy design features. Some abstractions are good because... well simply because you are used to them. Other abstractions are gamey crap because you don't like them, or because they are not canonical.
No, some abstractions are good because they simplify things for the sake of playability. The designer being too lazy to come up with a proper solution and taking the easy way out is a whole another thing.
What exactly does simplify the per-level multiplication of your character HP? In real life there is no such thing that needs to be simplified. And what about the unnatural rate of your character progression in basically everything? It is a simplification or a 100% gamey mechanic that works well in games? And the senseless amount of stuff you can horde in your backpack? And...
Abstractions that adhere to ages old gaming conventions and serve gameplay functions for entertainment. The only thing they need to maintain is internal consistency.
Visual design, on the other hand, is in your face. It can be beautiful, ugly, exquisite, boring, bland, contain supernatural elements impossible IRL but it too needs consistency.
Half arches with magical goo is stupid because it is inconsistent with reference architecture, similar to the way it would be stupid if level 1 fighter classes in DnD could cast high level spells that caster characters could only cast on high levels.