And one more very interesting feature, but unfortunately not for all genealgs, its a bit specific.
Sometimes I make research of relationships between people using gramps associations. I make a lot of difficult filters, then I export people to GV, then use python script to convert it to dot (looks like). That script also includes associated people. Then I import it to yED. And only then I am ready to some research. But even now I can only see nodes (fullnames) and edges (relationship name) - thats all.
I just imagine how great it would be to have an option “Show associative people” the your treeview! And then each associative person will show generations of his ancestors/descendants as the main tree. But it is unusual usage of the tree, I understand not everyone needs this feature. Just hope something similar feature will appear anywhere in Gramps.