Yes, except where what the 5th graders come up with fails to meet other important criteria.
A lot of notation is the way it is because of history and inertia, rather than because practical considerations or requirements means it needs to be that way.
If there are changes we can make to make languages more approachable without making them worse in other ways, it makes sense to opt for making them more approachable.
> A lot of notation is the way it is because of history and inertia...
Less than you may think. Leibniz and other mathematicians spent years debating notational forms in mathematics before settling on what we have. See Florian Cajori's _A History of Mathematical Notations_.
So history and inertia by now, in other words. The point is not that people didn't think about them when they first came up with them, but that they are not generally regularly revised based on e.g. practical teaching experience or research.
A lot of notation is the way it is because of history and inertia, rather than because practical considerations or requirements means it needs to be that way.
If there are changes we can make to make languages more approachable without making them worse in other ways, it makes sense to opt for making them more approachable.