I recently had a discussion with someone regarding the differing complexity of older D&D and D&D4e, in relation to the upcoming Red Box. It made me realise something interesting.
Let me start by saying that mechanically D&D4e is clearly more complex than older styles of D&D. D&D 4e does have a high level of mechanical exactitude. However, it is not as complex as many, particularly those who play older styles of D&D and other RPGs may fear, due to several novel things that 4e does.
D&D4e is less complex than it appears due to a number of reasons. The main one I examine here is the distribution of mechanical complexity. Another is in its structured approach.
D&D4e has a core set of mechanics with which all players and the GM interact. This core is around 20 pages in length and covers combat, skill use and some other basic elements. Outside of that in any one session, the GM will need to know around 8 or so pages of encounter creation mechanics (including page 42) and around half that again in premade monster, trap and skill challenge stat blocks. The players will have a 1 page PC sheet and 1 to 4 pages of PC information that covers all of their PC's possible actions in game.
The end result is that a DM will need to know around 30 or so pages of stuff and PCs know around 25 or so pages of stuff. For either side, the complexity isn't that great. Compared to older styles of D&D, the players have taken on a greater burden but it is small compared to the drop in burden the DM has benefitted from. The overall result is that DMing D&D4e is actually a pretty simple task, to the point where it is actually suitable for low prep GMing.
From the surface, I can see why people may say how does this differ from any other RPG? Surely 3e could be distributed in a a similar manner. Well first, D&D4e's design has a strong structure (as previously discussed). This structure takes a lot of the burden from the DM on knowing the entirety of the system and the PC's capabilities. Whilst many chaff against this structure, this is perhaps one of the clearest virtues of D&D4e IMO.
As a part of this structure, 4e provides the DM with universal tools to not only to adjudicate single tasks (like a unified core mechanic would), but to create entire situations. The Encounter rules (including combat and skill challenges) provide a framework that works out of the box, no matter what PC capability or level. This means that the need for the GM to know the entirety of the system and the PC capabilities is much reduced.
I made this point a while back. Many DMs in 4e do not carry PHBs or concern themselves with PC information at all. The DMG is the book they use. I think this is a marked difference from older styles of D&D.
The downside to D&D4e's approach is that it doesn't suit new RPGers as well as older styles in many situations. IMO one of the reasons traditional style RPGs work so well with new RPGers is that the level of complexity for players is very low. Provided you have one guy willing to take on the burden of knowing the rules and adjudicating them (the GM), it works just fine.
This resonates with my recent experiences with games at Kapiti College. The RPGs that work best are ones where the players have the lowest bar of effort needed and the GM can take on the entire mechanical burden along with the narrative burden. Its also why traditional RPGs can work so well, no matter their quality, provided they have a strong GM.
The downside to this approach though is that IMO this dynamic can be unhealthy, especially in the long term. This point actually relates to the very thing that I started the Grand Experiment way back when, and is the driving force in my search for new gaming techniques.
If you move to more complex story forms including stories that focus on PC rather than a structure like D&D, WFRP or CoC, the already high burden on the GM becomes so great that it makes it hard for the GM to successfully pull it off. This then filters down to producing mediocre experiences for everyone involved.
The backlash to this growing burden is IMO one of the driving forces behind the Indie RPG movement. Rather than leaving everything to the GM to manage and interpret, RPGs start coming to the party by providing more explicit support and redistribute the burden to everyone at the table and allow the GM to "play".
So, where does D&D4e sit in all this? I think one of the things it doesn't do is shift the burden of narrative authority very far from the GM. This IMO is a good thing as I have personally found that shared narrative, except in an explicit limited form, to be problematic. However, D&D4e makes leaps and bounds in shifting the rest of the GMs burden, especially mechanically, in a way that is more healthy. By doing so, it allows the GM to pay better attention to the narrative part of the game.
Sure, the apporach may make it a little harder for new RPGers but its not a lot harder. It may even make things easier to those groups of completely new RPGers that don't have a person willing to step up as GM. However, I think D&D4e is better at supporting the GMs they can consider investigating more complex story forms and greater PC focus without many of the hurdles.