The other thing the Shuttle had that was unique was a lot of space in the payload bay. For Hubble servicing missions, the telescope was captured by the CanadArm and docked to a turntable in the payload bay.
Thus they had a stable platform to work from. But they also had places where equipment (New components) and tools could be stored easy to access. There was lots of room to store all the tools, and parts they needed.
Soyuz is severely limited in this respect. You could not really mount things on the outside and survive launch.
Now you could build a platform that Soyuz could dock too, that would carry all this with Soyuz behaving as the launch and return vehicle for the fragile humans. But everything else on the other vehicle. \
If Orion was to be seriously considered for such a task it would probably follow such an approach of some kind of logistics or service module to carry most of the stuff needed and Orion just being the human transport component of it.