I can start with saying that the number one killer feature in OS 3..4 for me, is 68000 support for v45 Workbench and ASL prefs.
Sadly the Workbench prefs does not include the Ghostbuster functionality (
http://aminet.net/package/util/cdity/GhostBuster) and the OS developers seem incapable of understanding why anyone would wish to hide a device icon, especially since it would prevent the user from selecting the hidden device and formatting it (not really, but that is what an OS developer has given as reason) - and I wish for that functionality for 6800 systems as well - Ghostbuster comes with sources, but it uses Reaction, for which there is no 68000 support, plus I am no big fan of Reaction in the first place. So what to do, what to do... aside from cloning the Workbench prefs program from fresh, there is one option, I suppose - use the Ghostbuster commodity, and just binary patch the prefs (or wait for OS 3.1.4 sources to leak).
Regarding ASL.. I prefer v45 ASL over ReqTools and others, so I use
http://aminet.net/package/util/misc/AslToRT to trap calls to reqtools.library etc and use ASL requesters instead. A more "clean" way, like implementing reqtools.library as a wrapper for ASL, would probably be preferable. Lastly, the "official" family of C:Request#? programs has always been lacking one member - RequestString - there is a myriad of third party variants around, mostly incompatible with each other - it would be very useful with an official RequestString that make all the others redundant.