I am still using the old Pirate Warrior (Dr.Boom version) to farm gold and, to my surprise, I found myself at rank 4 even last week.
I am turning to Paladin deck, however, if you strongly suggest so.
I hope some other hero will be able to reach rank 5 because I have 4000+ victories with both Warrior (pirate) and Paladin (secret) and I'd like to use different heroes to reach high victories count even with other ones.