Reusable / shareable Modifier Stack concept similar to Node Tree concept.

Material node trees, Geometry node trees, and Particle Settings are all reusable across multiple objects. You change the setting in one place and all objects that use that material/geo/particles get the same changes.

This concept needs to be applied to the Modifier stack.

The particle settings also allow multiple particle settings to be applied to a single object. It should be possible to have multiple Modifier Stacks in a similar way. Maybe I want several objects to have the same Mirror, Weld, Solidify and Bevel and settings but on a few of them I want different Subdiv settings. I can make one Modifier Stack with everything except Subdiv and share that across all object then on a few object I add another Modifier Stack containing only the Subdiv modifier.

The UI would basically be the top section of the Material Properties (because it has arrows for rearranging items in the list) followed by the existing modifier stack UI.