Replication slows down on massive deletes
First there's no such thing as one way peer to peer (that I know of).  Are you sure you aren't using transactional replication?

Are the deletes done via stored procedures?  If so you can replicate the stored procedures as well as the tables (all in the same publication, this will require a reinit of the subscribers).  This way the stored procedure call will be replicated instead of the actual row by row delete.

With only 700k rows in the table, even if you blew them all away and reloaded them the replication shouldn't get that far behind unless you have a really slow link between the servers (which you didn't specify).