Maybe it could be made an option to pg_dump?
Some users and their systems might not even have overloaded functions,
and these users will of course prefer a nice looking filename, i.e. all functions
having the same name kept in the same file. Which for them will mean only
one function per file anyway.
pg_dump --split --overloaded-functions-to-same-file
Other users and their systems might have a lot of overloaded functions,
like the equal() example mentioned, they will of course prefer to keep
all functions in separate files.
pg_dump --split --overloaded-functions-to-separate-files
Then, one can discuss which one should be the default option for --split,
I would prefer the same file variant, and think most other users would too,
except for users with a lot of overloaded functions.