Re-open thread on insert only in incremental load

With a unique key in the .yml file, the merge statement in an incremental model looks like this:

merge into `bigquery_table_tgt` as DBT_INTERNAL_DEST
    using (
      select * from `bigquery_table_tgt__dbt_tmp`
    ) as DBT_INTERNAL_SOURCE
    on 
                DBT_INTERNAL_SOURCE.key = DBT_INTERNAL_DEST.key

when matched then update set
    `key` = DBT_INTERNAL_SOURCE.`key` --etc 


when not matched then insert
    (columns etc)
values
    (values etc)

A user asked how to achieve insert only in an incremental model and the proposed solution was to remove the unique key in the .yml file.
Without a unique key in the .yml file, the merge statement looks like this:

merge into bigquery_table_tgt as DBT_INTERNAL_DEST
using (
select * from bigquery_table_tgt__dbt_tmp
) as DBT_INTERNAL_SOURCE
on FALSE

	#no join on source/target ->> you will have to check source against target yourself to avoid duplicates

when not matched then insert
    (columns etc)
values
    (values etc)	

The solution I really would like to see is this

With a unique key in the .yml file:
#new feature in dbt:
merge_option: insert_only

merge into `bigquery_table_tgt` as DBT_INTERNAL_DEST
    using (
      select * from `bigquery_table_tgt__dbt_tmp`
    ) as DBT_INTERNAL_SOURCE
    on 
                DBT_INTERNAL_SOURCE.key = DBT_INTERNAL_DEST.key

# remove the following statement when merge_option = insert_only
#     when matched then update set `key` = DBT_INTERNAL_SOURCE.`key` --etc 
#but of course keep this:

when not matched then insert
    (columns etc)
values
    (values etc) 

Will this kind of feature ever show up in dbt?