Customizable Dashboard
It would be fun to have the ability to modify the dashboard to fit not just your two most valued collections but rather the collections of your choice. Or perhaps even the ability to create tiles that show cards from a single player across many collections(if your into that sort of thing). I visualize the ability to have these customizable tiles along with the ability to turn on or off a simple visual for each one, such as a bar graph for values or percentage gauges for set completion.
That is a cool idea. I think that would be interesting to make it customizable with some different tile options. I'll wait and see how many other people like this idea but I could see that being popular.