Support for z-code v6 (the graphical Infocom games: Zork Zero, Journey, Arthur, Shogun)?
Ability to run Gnusto in a Firefox Tab?
Togglable ability to auto-complete words by hitting tab? (off by default)
Ability to scroll back in your game history?
Inform-game debugging features? (View object tree, modify variables, etc)
Ability to interact with Baf's Guide from within Gnusto?
Support for other IF file formats (Glulx, TADS, HUGO, ADRIFT)?
Ability to host gnusto as an applet in a web page (like Zplet, but more robust)?
What other features or improvements would you suggest?
What do you find to be the most negative / frustrating about the current version of Gnusto?