pure honest question applies to anyone.
Firstly because classes hindered some types of character
eg The person brought up as a barbarian or peasant who discovers they have a natural talent for magic
In both games and life sometimes a persons path will change
Secondly they weren't recognised in the game which (especially in MW) had a much better way of defining character. To me it means more for a character to earn their position as Knight of the Imperial Legion or Warlock of the Mages Guild than just select a class at the beginning of the game. Obviously this means I want the game to have as many factions as MW and may be disappointed on that count
Level-scaling was just annoying, regardless of classes. I've always preferred classless systems like Runequest to ones like D&D, although a relatively loose class system like TES had is better than a rigid one like D&D. Better still to get rid of them entirely