Notation feature has been around since before RB, likely PT 4-5 or so (from memory).
It has been largely unchanged since it was implemented.

Piano Roll allows different options and (IIRC) came to fruition later, so the fact that they are different doesn't surprise me.

My gut tells me Notation was a third party add-on/acquisition since it hasn't changed in so long. There have been many requests for improvements over the years.

Not that I don't think PGMusic *could* improve it, I suspect licensing restricts them from doing so.
Not speaking for PGMusic, just a hunch. So I've adapted to it. Use the tool that works for what you need.

I do not work here, but the benefits are still awesome
Make your sound your own!