Note: not ordered. do whatever I/you want

+ Cookbook of basic things
+ Write good help/manual
+ Some sort of Wiki
+ Make error notice short while let users see detailed help/manual for what-to-do
+ Even better CUPS/IPP support
+ Even better frontend, language-friendly text printing
+ Tcl/Tk frontend. More in dev-diary.txt, July 7th.
+ Make a build guide for android:
  Summary the hacks to p4a, bleak p4a recipe, p4a webview bootstrap, and AdvancedWebView
+ Try to implement enough without more dependencies
+ More funny "languages" (now there's lolcat; I think the next is 文言)
+ Arch Linux package / AUR, package for other distros
+ Service for other init systems (a systemd unit file is there)
+ ...

? Optimize PF2 text printing? It seems a bit slow (in algorithm).
? Use Go as part of backend? It can boost things up, and build some (essential) image manipulation in, quicker. And strip some way-too-big Python libs away (for smaller Windows/Android dist).
? Built-in PostScript (Even if very basic)
? Data compression for GB03. Optional
? Plugin, for including community features (that involves usefulness but also bloatness)
  It's usually messy. Try forking in your own way, at the moment.
? Process picture with WebAssembly? (Web frontend only)
? Put Android APP on F-Droid? But it needs automatic build system...
  Android guys can help this!
? ... Or put to APKPure? But make frontend well before doing all of these