Ragnar's great strength is that he can prepare Amphibious Berserkers to upgrade into Grenadiers with City Raider I and II, and quickly transport them to a juicy overseas target using transports with +1 movement thanks to his UB. Anyone who's AGG can get Amphibious melee/gunpowder units right out the gate, since free Combat 1 -> Combat 2 -> Amphibious with only 5xp, but only Ragnar can upgrade his Berserkers to get Combat 1 Amphibious City Raider I and II grens. And get transports with a free +1 movement promo if you build his unique Lighthouse UB. Needless to say, it makes Ragnar slightly better at the whole "naval invasion" deal.
Of course Ragner's big weakness is his starting techs giving him a slow start, and the fact that not every map is going to be a fractal map where you can sail across the high seas and descend upon rich neighbours with a fleet of doom.