Arrays vs separate system catalogs

During my coding of the per-user/database settings, it occurred to me one
more time that arrays are evil.  Basically, the initial idea was to have a
column pg_database.datconfig that contains, say,
'{"geqo_threshold=55","enable_seqscan=off"}'.  Just inserting and deleting
in arrays is terrible, let alone querying them in a reasonable manner.
We're getting killed by this every day in the privileges and groups case.

What are people's thoughts on where (variable-length) arrays are OK in
system catalogs, and where a new system catalog should be created?

-- 
Peter Eisentraut   peter_e@gmx.net