A compromise between both; it sounds unrealistic but you could have one side of the game having an intuitive interface and interaction system for easy access, as well as understandable but diverse skill/level systems - then you can have, under the surface, a deeper optional experience for those who want more and have more time to give. It would be difficult, I would imagine, but then it keeps both the casuals and the "hardcoes" happy.
For example, in Morrowind, after the brief tutorial, you can just slap on a few pieces of armour and a weapon then you go off slaying and exploring - or delve every crevice, read everything and take all the advice.