Regarding the point with Warhammer 40,000 (and Warhammer Fantasy), the armies in those games are already in roles. They do not represent true open customization. Though they use points, each army is mostly self contained, has specific strengths and weaknesses and then is further restricted by what is core, special and rare in the list itself. This guides the way the army plays and how far it can customize.
Sorry but I have to disagree. Certainly some armies might be more straightforward but other lists such as the Eldar army can be as customizable to their options as 3e multiclassing.