Correcty , you are absolutely right when you say that we have to reinvent the wheel in Unreal4.
I think be very important and extremely interesting the modular ontological approach with components using placeholder, if it can be expressed this way. As a approach using placeholders with a fully functional combat system, damage system, diferent weapons types system, several physics simulation volumes, several vehicles with diferent behaviors (aquatic, aerial, terrestrial), NPCs interaction system, AI system, HUD, Stats and SaveGame which can be easily dragged from content browser into any custom project, whether it be the Blank, First Person, Third Persons, Flying … etc, and configured using placeholders and parameters, and not least: Examples for game types like CTF, DeathMathch, Cooperative.
In UDK could find inside the folder UTGame very interesting UT classes and game types using a few scripts (All UT Game Logic). And some of those scripts (class) could be declared for use inside the editor and used as kismet nodes. Using such method could be possible in a few instants and with a few simple adjustments add new fully functional weapons, projectiles, characters, enemies, objects with páwn interactions, HUD, only replacing the placeholders objects with entirely original skeletal and static meshs, particles, sounds, animations, sprites…
I think the Poster when mentions ‘working’ in the title, not exactly is about licensed Art content that could never be used in a commercial game, but Draggable ‘Working’ gameplay functionalities which can be used in any original game. A hybridity between modding and authoring tool.
But I understand the Epic’s proposal. In another thread when I have discussed about something similar, some distinguished members considered that my proposal could not meet with the Epic interests, which aims to make the new Unreal Engine one Framework more Agnostic than UDK was, especially when it involves the Powerfull Blueprint Language which in my opinion is more like a visual programming language than a visual scripiting. It is almost like C++ using diferents arguments and arranged in a flowchart.