I think the idea of Layer Groups is probably separate to this idea of named settings sets.
Groups are (potentially) a way of controlling the visibility and frozeness of sets of layers. And if that is true, one could have "Tier1" with 8 different layers (OO Tracks, OO9 Tracks, Buildings, Scenery, BaseBoard, Signals, DCC Power, Feedback) and so for "Tier 2". And also (Tracks, Electrics, and so on which are groups independent of Tiers). That way you can hide the layers as sets. Obviously "All" is a freebie.
I am assuming that the need for different setting really depends on layer (so 009 vs OO etc). Those layers could all be in one group, but not necessarily.
We still have to decide about ordering in Layers and between Layers. One way could be a command to enforce order by Group, or otherwise.