The advances in Dashboard V2 are great. We are so close to full CSS support with the advances options. Please consider adding this. I feel it would fully open up to allot of development (I know I would personally).
In addition lets get editing of icons and such for single tiles not just per templates. That goes along ways when trying to fully customize the dashboard.
Okay access to google free material icons and fonts would be a nice start by importing them into your html. Then allow Editing of font properties per tile in the css editor you have. in fact full editing of each tile independently not per template. I get the point of universal templates per page but sometimes it doesn't work.
Or a simply Web API that would could build our own websites off. I know this could be made separately by someone and if someone has please let me know.
I feel like dashboard V2 was a good start and don't want to take away. I am just a graphics and UX person by heart and little things kill me (blame my type A personality :)).
You might also try HousePanel which supports user provided CSS and user created skins. Individual tiles or groups can be styled to any look you like. You can edit the CSS directly or use the built in tile and page editor which is basically a CSS editor.