The DateTieredCompactionStrategy settings aren't exposed via JMX. There are a few use cases for which this would be valuable.
1. Testing via write survey mode. Currently you can change the compaction strategy class but are limited to change min/max compaction threshold.
2. Testing via trying out the strategy on one node in your existing cluster. This helps you to understand the impact when transitioning from another compaction strategy to DTCS.
3. Transitioning your cluster to DTCS one node at a time for minimal impact (then of course changing the persisted schema).
This should go back to 2.0 or at least 2.1 because it's really a simple oversight to not have exposed those in ColumnFamilyStoreMBean.