There are some new features of Impala that are done but disabled by default because they are not strictly better than the previous versions. E.g. the various metadata improvements. Containerised Impala is likely to be new deployments, so it is easier to make potentially disruptive changes to defaults now.
We want to invalidate based on HMS notifications (https://issues.apache.org/jira/browse/IMPALA-7970) and memory pressure. It's less clear if invalidating tables based on time is really useful - for large fact tables it would add a lot of unpredictability because reloading the tables is expensive.
IMPALA-7970 goes in, we probably also want automatic invalidation by default (TBD - how to handle older HMS that doesn't support those APIs).
We probably want to enable HDFS preads for remote reads: -use_hdfs_pread - but I think this is going to be done automatically.
We may want to have an I/O cache enabled - tracked by