Currently, ArcGIS Server only allows for one shared instance pool of feature services that ALL feature services share.
My idea is that we have shared instance pool "groups." These groups would work the same as the current shared instance pool, except we could specify the number of shared instances per group.
This is beneficial to organizations who have multiple projects hosted on their server, or otherwise need to group feature services together in their own shared pooling without the hassle of managing dedicated instances. I envision that you can create shared instance "groups" in server manager where you can assign a number of shared instances, and then be able to assign individual feature services to that shared instance pool.
This is beneficial because you can still take advantage of the shared instance pooling, but at a project/group level where you don't have multiple projects/groups competing for resources in the single large shared instance pool, and without having to manage dedicated pooling at the feature service level.