Except it isn't about removing complexity, for any reason. Its about removing traditional, and by traditional I mean 20+ year old D&D boardgame, RPG mechanics, in favor of ones that do the same thing, but better.
Attributes aren't required for an RPG at all, nor are they important in the slightest. What is important however, is the things those attributes effected, and having various ways to change THOSE things. A RPG having a "strength" attribute doesn't matter at all, what matters is being able to influence melee damage, total stamina, health, and carry weight, the things strength influenced(In Morrowind for example)
Attributes are actually a fairly terrible way to do RPG mechanic in the first place, because they bundle multiple major character stats into one, thus forcing blanketing upgrades to various aspects of your character, even if you don't want them, increasing homogeneity between characters.
Skyrim is objectively more complex then past TES games in this regard, because HP, stamina, and melee weapon damage are now their own individual stats, controlled by their own individual skills, perks, or attributes. By getting rid of attributes, Skyrim managed to give the player more ways to define their character that aren't tied together, thus INCREASING the number of possible ways to define your character.