1. There are Achetypes in this game since you can recreate them, people will do that, pretty much everyone does it would be my guess, dosent have to be on purpose.
The game actually endorses that because going Heavy Armor+2H Weapon+Stealth dosent make much sense, even less so 2H+1H and Shield or any type of melee weapon or Bows plus a lot of Magic.
Most people will probably end up with either a Warrior or an Assassin type Character+some supporting Magic or as a pure Mage. Magicka, Stamina and Health are very limiting in that aspect.
Archetypes in general do exist because they make sense, the skills that make up one archetype usually add up to a good and fun combination.
2. While I agree that balance DPS wise between classes is not needed in any single player game, if such a balance isnt there the game would either need to have much better and different ways to adjust its difficulty or at least a blance of DPS+Defense.
Also there isnt any difficulty in this game no matter which difficulty you play on, it is way to easy and I have yet to find a way get a challenge.
Maybe Bethesda really balanced it so characters with only 2H Weapon+Heavy Armor+Stealth skills with all level ups in Magicka and perks in Lockpicking are playable, it for sure looks like that.