The only reason to include LoadWB would be to show off to peecee users. On 3.9 though it would not work. You cannot LoadWB 3.9 without loading some libraries (I HATE that). IIRC, even the HDToolBox from 3.9 won't run without some libraries loaded.
I don't believe you'd fit a usable Workbench disk on a kick ROM. You'd have to pull a bunch of other strings like mounting it to make it useful. Not practical on a kick ROM. That's where booting to a flash ROM or some other solid state drive is ideal. Even a ROM Workbench disk (full 3.9 install!) on a card would be GREAT. But goal #1 of the 3.9 ROM for me would be eliminating the boot-reboot. My A3000UX will not boot that way. I actually have to power up all my hard drives and wait 5 mins or so before powering on the A3000 or it will either reboot-reboot-reboot forever, or I get a insert disk animation. Either way, it's hell on the RAID array!