Mario 64 is an incredible design that still mostly holds up.
However it was doing things never done before, is 25 years old, and game design has evolved since then so there are definitely rough edges.
Most of it is great, but there are spots where the design falls short simply because they were blazing new trails.
Galaxy is a much more refined experience though, no doubt. And is incredibly inventive with its worlds. Honestly few games have ever had the breadth of experience that Galaxy has, and the planetoids and gravity altering gameplay is incredibly fresh and innovative still.