Modern manager, improved workflow and better integration with Scene Explorers.
I think Selection Sets is just another way of doing scene management a part from Layers and Hierarchy as it allows one object to be part of two selection sets unlike layers same like Blender collections. Selection Sets is in another old window and it cannot handle folders and it is quite inconvenient to work with as it needs some UX and UI updates.
And since it's so old it's a bit clunky to use and has a couple of bugs. If you select an object in that manager it will not highlight it in the viewport and the other way around to start with. You actually have to select it in the viewport then click the Highlight selected button in the manager and that will apply some coloring to it in the manager list (lol). If you decide to "highlight" other objects, the previous ones will keep a black color apply (why?) The buttons themselves in that manager don't have a consistent behavior. Adding and subtracting can only be used when there are objects selected in the viewport and when not, they are greyed out. But the Subtract button doesn't stay grey out when the selected object in the viewport is not part of the given selection set so I fail to see the logic behind this.
The highlight (color) selected object button on the other hand is always active even if it only works with objects selected in the viewport.
Then, all objects have the same icon whether they are geometry, shapes, lights etc. It's very clicky (like you say it misses some drag and drop instead of copy paste). Plus, I'm not sure it works that well with Scene Explorer. Maybe it's a bug but when The Selection sets filter is enabled in the Scene Explorer, it doesn't show in the list all the objects in that selection set. In other instances, it doesn't only show them but other objects as well.
Save Named Selection Sets with Container. Named Selection Sets are not stored with Container.
Save selection sets for a character or group of objects. There should be a way to save selection sets for a character or group of objects. When that same character or group of objects is opened in another instance of 3ds max, the selection sets are automatically there. Or save the selection sets and open it in another instance of 3dsmax and it is automatically applied to the character or object that it was created with.
Selection Sets for Selections of Layers. It would be very helpful if we could make selection sets for selections of layers.
Color Codes on Selection Sets. Having color codes on Selection Sets would be a great plus. Such as color coding different sub object selections such as edge / polygon selections. These colors can make it possible to work faster in viewports while working on complex objects.
Unhide selection sets of Face SubObject. You can do selection sets of objects and unhide them selecting it. In top of that objects have other management systems as layers etc. But in faces you only have selection sets. And this doesn't work great as it can not unhide selection sets. This is a quite basic function.
Keep Sub-Object Named Selection Sets on Collapse/Modifier. Sub-Object Named Selection Sets in Editable Poly are lost in many cases. This should not happen. Instead, the named selection sets should survive new modifiers as well as using Collapse To in the modify tab. In the case of adding modifiers: a named selection set should be available up the stack in the same way that sub-object selections get passed up the stack. This would mean that in the case of topology changes, the named selection set should adapt. For example, if a named selection "Polys1to10" set on Polygons 1..10 are set and a Tessellate modifier is added, the named Selection set "Polys1to10" would be all the resulting polys of that modification.
Selection sets should come along when merging a scene that contains them. Whenever you create selection saves, and save that max file, and then merge that file into a new file, those selection sets are not getting merged. It would be very beneficial to bring those selection sets with the merged scene, since selection sets have the advantage over layers where the same object can live within different selection sets.
Include/Exclude lists with Selection sets both when adding or removing elements. When editing the include/exclude-list of a light, I should be allowed to use selection sets not only for adding elements but also for removing items. Why would I make 1 click for adding 100 things, but 100clicks to remove them when i decide they´d rather be ignored by that light, that just makes no sense!
Add ability to select Layers to exclude/include lists. Add ability to select Layers to exclude/include lists. at the moment i have a script that convert layers to selection sets which then allows me to pick selection sets but would be easier if there was option to select layers exclude/include lists.
Links to original individual ideas:
