I must admit that I do like the concept of pieces of music that play in any up to date base Sonic Pi distribution. It’s easy to click on the ‘CopyCode’ and then paste it into sp.
I’m not yet at the stage of making recommendations for future releases. But, I think that expanding the range of built-in synths would be very useful, as it would mean that more sophisticated sound design could be done without using add-ons.