D&D 5E (2014) Should 5e classes be Complicated or Simple?

[CleanCutRogue]

Classes should be few in number and have a relatively large amount of customization options. I'm in favor of only four classes, ever, in the whole game (Fighter/Thief/Magic-User/Cleric) with a pre-defined strong archetypical set of abilities, but then add multi-classing possibilities and customization options ("Class Features" ?) allow you to deviate from the strong archetypes when character concepts get a bit more complex.

 

[Aldarc]

Classes should be simple and easy to play but have a learning curve for "mastering" gameplay.

 

[Crazy Jerome]

As simple as possible but no simpler.

This. And the more recent corollary, there is a limited amount of complexity that any system can tolerate. Use it well. (Obviously, modular options, so that you can choose the complexity that matters to you, helps a lot here.)

I think interesting depth, as opposed to mere complexity, results from meaningful decision points between relatively simple, separate elements. A big part of the unnecessary complexity from versions of D&D (all of them) has been cause by complexity added for depth that managed to collapse into relatively few meaningful choices. See 20 kinds of polearms as one minor example.