The Vocab Shuffle feature now requires a Heisig frame number. It will show randomized priority entries from Jim Breen's dictionary, but only words made of kanji that you have learned so far. Many thanks to nikitakit (Nikita Kitaev) who showed me a simple solution to do this.
If it was possible to display how many words you can form with the kanji you've studied so far, that would be extremely motivating. For example, in the page that is displayed when you end a review session, if you had a message like:
You have studied XXXX kanji, which can be used to form YYYY words!
Here are some of the words that can be formed with the kanji you have already studied:
Example 1 - Reading - Meaning Example 2 - Reading - Meaning"
The first part of the message could appear as a regular part of the review page, study page, etc., to remind you how far you've come and to motivate you to keep on studying.