I think there should be some drawback to Argonians for the sake of balance. Immunity to Poison (or was it mega-resistance?) and Water Breathing? I honestly don't know why people chose to play as anything else.
Immunity to poison, 75 resistance to disease, underwater breathing. But if we really want to get into this discussion, here's what the other races have had in the past 2 games
MorrowindAltmer: -50 fire, -50 magicka, -25 frost, -25 lightening, +75 disease, fortify max magicka 1.5x (150% more magicka)
Argonian: +100 poison, +75 disease, Water Breathing for 120sec on Self, Cost 5pts
Bosmer: +75 disease, Command Creature 5pts for 600sec
Bretons: +50 magicka, Shield 50pts for 60sec on Self, Fortify Maximum Magicka 0.5x INT (50% more Magicka)
Dunmer: +75 fire, Sanctuary 50pts for 60sec on self
Imperial: Absorb Fatigue 200 pts on target, Charm 25 to 50 pts for 15 seconds on target
Khajiit: Night Eye 50pts for 30sec on Self, Demoralize Humanoid 100pts for 30sec on Targe
Nords: +100 frost, +50 lightening, Frost Damage 25pts on Touch, Shield 30pts for 60sec on Self
Orsimer: +25 magicka, Berserk - Fortify Health 20pts, Fortify Fatigue 200pts, Fortify Attack 100pts, and Drain Agility 100pts for 60sec on Self
Redguard: +75 poison, +75 disease, Adrenaline Rush - Fortify Agility 50pts, Fortify Endurance 50pts, Fortify Speed 50pts, Fortify Strength 50pts, and Fortify Health 25pts for 60sec on Self
As we see, it's redguards and nords who are clearly the best choices.
OblivionAltmer: -25 fire, -25 frost, -25 lightening, +75 disease, +100 max magicka
Argonian: +100 poison, +75 disease, Water Breathing (constant)
Bosmer: +75 disease, Command Creature up to level 5 for 60 secs (lol)
Bretons: +50 magicka, Shield 50% for 60sec on Self, +50 max magicka
Dunmer: +75 fire, Summon Ancestor Guardian for 60sec on self
Imperial: Absorb Fatigue 100 pts on target, Charm 30 for 30 seconds on target
Khajiit: Night Eye for 30sec on Self (no cost), Demoralize Humanoid up to 25 for 30sec on Target
Nords: +50 frost, Frost Damage 50pts on Touch, Shield 30% for 60sec on Self
Orsimer: +25 magicka, Berserk - Fortify Health 20pts, Fortify Fatigue 200pts, Fortify Strength 50pst, and Drain Agility 100pts for 60sec on Self
Redguard: +75 poison, +75 disease, Adrenaline Rush - Fortify Agility 50pts, Fortify Endurance 50pts, Fortify Speed 50pts, Fortify Strength 50pts, and Fortify Health 25pts for 60sec on Self
this time the bretons are the winners, due to +50% resistance to all magic, have a nice shield, and +50 magicka. Redguards are also still very superior.
Also, who the hell is going to drown an enemy to death? And poison/disease resistance is more like resisting minor annoyances.