This is mostly a DM overruling. You could also deny it "because of reasons" as many DM do to curb min-maxers' enthusiasm
MI (druid) is the best choice a fighter or paladin could take as a sword and board duelist player.
It works in sinergy with Polearm Master, allowing you to pick a quarterstaff (1d6+str +2, bludgeoning damage, 1h, versatile) and making it a magic +0 warhammer with Shillelagh (1d8+str/wis +2, magic damage, 1h, versatile) with the increased benefit of the "back hand" as a Bonus Action (1d4+str +2, magic damage) and an Opportunity Attack on a Reaction taken as soon as someone lands in a square next to you.