I know you guys must be fed up with all the suggestions :D Here is another one. Could it be possible to see the amount of words/characters (number of entries) there are in a list?

Not a bad idea! Will add that to our list of things to do when there's time though ;)

This feature would be even better if you could also see how many or which proportion of the words and characters in a list are new (= not learned yet).

That... would be a little more difficult. If you open up a section of a list, you can see as the information about how well you know all the words is downloaded. That would have to be done for all sections in a given list, so it would take a while.

Could make a dialog box that gradually downloads all the information and then formats it nicely into a stats report for you. But something that would show up on the list page automatically probably wouldn't work, the way the backend is setup.