I believe pgpool also deals with timestamps properly. Secondly, no one is forcing you to use SERIAL datatypes - the table locking is there for backwards compat

I believe pgpool also deals with timestamps properly. Secondly, no one is forcing you to use SERIAL datatypes - the table locking is there for backwards compatibility. SERIAL is not the best performance choice for replicated servers, and there's nothing to stop you using another style of ID field.