Hello Sarah,
This is a wonderful idea! I completely see how this would be immensely beneficial.
I think the only way via this add-on that the students can have the rubric handy before they begin work is to check the options for students to access the rubric, & email it to them when you initially attach the rubric to the assignment. Or with the Goobric for Students extension, they do have the option to self assess their work.
I do see that what you are speaking to is would be more accessible than the current features. I will relay these ideas to the development team to keep in mind when they consider updates. Thanks!!