I am talking about "external" features, of storage, or maybe file system, not ISP/TSM functionalities.
The thing is, as container pools introduced some great space savings and maybe some benefits in replication process, they also removed great flexibility that we have with "traditional" pools, and also made ISP server unreasonably hungry in terms of needed CPU/Memory and database IO resources.
When I am talking about flexibility, you were able to migrate data from one pool to another, to copy them in an efficient way, to do backupsets and so on.
About resources: I am supporting, as a consultant, several ISP servers here and there, mostly of "small size" according to IBM ISP blueprints, some of them maybe in "middle" segment. Recently I have upgraded couple of them to latest server versions, migrated data to container based pools, set replication and even container copy to tape in few places, one on DR side, and another (client) on primary side.
As backup operations mostly goes quite ok, I can see enormous growth in hardware usage: Database grows 3-4 times, ISP servers are the hungriest IO consumers of ALL servers in (small) data centers. OLTP and OLAP systems of a bank are no match to ISP database regarding storage IO, which is crazy.
Replication (container pool then node replication) is somewhat buggy, but this is a different story
So, I would like to explore other options on data reduction, beside ISP functionality.