Hi,
Is table discovery really that painful operation for PostgreSQL or is monitoring them overly painful in PostgreSQL? I think your discussion applies to many DBs though. What properties should be monitored per table? Should they just be disabled by default? In SQL Server this is pretty painless operation, no matter how many resources are discovered automatically (as the operational schemas just return more rows, this is quick operation and I assume MySQL has the same sort of discovery options).
In the UI, auto-grouping them and hiding them works quite well. Sure, it theory you could add hundreds, maybe thousands of tables (I know theoretical limits are huge, but in reality it's uncommon to see that many tables, as often table partitioning is used instead).
And are you proposing manual-discovery of each table, or manual-discovery to find all the tables? Should all the DB plugins use the same principle?