A Dragonborn is capable of producing magical pulses by shouting in the dragon language. He/she is capable of creating a devastating storm with a shout, become invulnerable, breath fire/ice, freeze an opponent solid, launch an opponent back a few feet (Fus Ro Dah), summon spectral warriors, and even detect a life force, and summon his own dragon to fight for him, just to name a few.
Combat feats, while sneaking around, with max sneak, a Dragonborn will turn invisible, bow attacks can paralyze when drawn-back completely, his one-handed attacks can stagger opponents, or kill them through their shield. His armor absorbs damn near all damage, especially with the improved, enchanted armor which also improves damage dealt from other combat skills. With the Mace of Molag Bal, the Dragonborn deals damage, not only to Link's health, but he also drains Link's energy, and ensnares his soul to a soul gem.
Magic is another world of combat feats in itself: Restoration magic allows the Dragonborn to create areas where he/she gets healed and no enemies can enter. Destruction, the Dragonborn uses electricity, fire, and ice spells, which can affect an entire area, such as a blizzard or fire storm and he can create walls of fire, ice or lightning, which damage those who cross through the wall. His Alteration magic allows the Dragonborn to enhance strength of armor and cause paralysis. Conjuration allows him/her to summon beasts, spectral assassins, and elementals. Illusion magic allows the Dragonborn to make the enemy flee out of fear, or fight against an opponent they know they will lose against.
So these are the combat abilities of the Dragonborn, and this doesn't even cover half of what he can do. Not exactly "weaksauce"