To mitigate the need for per-table tuning of autovacuum configuration, I'd like to propose a new GUC for autovacuum_vacuum_threshold_max.
Currently, it seems that I can either set autovacuum_vacuum_scale_factor much smaller than default on tables with millions of rows, or set a value globally that means small tables are auto vacuumed rarely. The default value for this new setting value could be -1 or 0 to disable the feature, or something like 100,000 perhaps so that tables with more than 500,0000 tuples are candidates for an autovacuum before they would with current default values.