More support for putting together cubes would be nice

You can add your cube as a deck to keep track of it, but what kind of support are you talking about? What would you want to be able to do? Cubetutor has a lot of options for this too.

'Sample packs' - not just sample hands would be a start, probably quite easy to add.

Also the ability to "hide" the sideboard on a cube "deck". I keep a changelog and notes on my cubes and it's annoying when I have to scroll past the empty sideboard table to see them.