Modmaker (in particular making weapon or vehicle mods) would be much easier if we could group objects for the purpose of moving them together. So if there's 6 objects in a group (e.g. a sword) and you move one of them, the rest automatically move along while staying stationary relative to the object you moved. All joints involved with those objects would also move.

Yaaasss please that'd be hella helpful for environmentals too !

You made the whole thing too low/high/left/right ? just grab it bits by bits to rectify it instead of having to change them one by one.

I'm curious as to why this shouldn't already be a thing, it would be very inconvenient not to have it?

Totally should already be a thing.