I have to admit that as a fan of the 3.5 and 4th editions of D&D that I enjoy complexity. I know that there are going to be many people disagreeing with me on this but having started with 3.5 D&D it feels like an integral part of D&D to me. Rolling into 4th right after 3.5 only reenforced that. This isn't to say that I don't enjoy simpler systems. I do very much enjoy systems like Savage Worlds and PDQ which are orders of magnitude simpler than the current iterations of D&D. However the lack of complexity just makes for a not D&D feel to me. Again this isn't a "you're wrong if you think otherwise" sort of statement, it's merely how I've come to this particular facet of the hobby and how it has affected my perception of what is and isn't D&D to me.