Yes true. Also, I may be wrong but the UE3 dev tool is just as bad as Cbox was, yet even a little worse. I remember always reading how horribly they implemented Fable into UE3 to where it puts us right in the same spot as TLC modding (not being able to do much at all) huge limitations. Just gotta hope that FableEd build may exist somewhere. Though your probably right it probably is long gone. Maybe anniversary could be somewhat re-done in the latest Unreal using the Fable assets, from scratch. So that maybe the limitations could be no more.
EDIT either that or a new editor for TLC. But it's been how many years since the release and development of Cbox and FE that maybe it just can't be figured out since the engine was in house. (figuring out meaning the stb and everything else unknown/ un editable such as uncompiled defs, new quests, regions so much more) Or maybe the unknowns can be figured out, and become new features in Cbox / FE or a new editor.