To add some context, I've seen that desire to select multiple items in relation to:

• Items in a translation job
• Items for a given page
• Anything meant for a specific user

Tangibly, it'd be nice to be able to select and approve items in workflow "grouped up" by the above item types.

Though the full list of workflow items is still useful, the thinking as a workflow user is I'd like to group and see everything I'm working on.

I'd also like to be able to approve nearly everything for a jobs, pages, or request where I can note and reject specific issues while approving everything else. 

I think the bundling wording came from the users, but what they actually need is probably this:

community.rws.com/.../multi-select-of-activities-should-be-enabled-in-workflow-activities

For clarity: Tridion Sites already has Bundle Workflow since a long time.  So, I guess that what you are asking for is something else than putting a set of Components in a Bundle and starting a workflow on the Bundle (where all items in the Bundle will go through workflow at the same time)?

Can you elaborate?