You really can’t get away from it: DDN reads like an iteration of 3rd Edition. So for DDN to really work, it needs to keep everything that I liked about 3E, of which there’s a lot, and trash the stuff that put me off the game and eventually made me such a willing supplicant at the altar of 4E, of which there’s also a lot.
The Good - There's a lot of stuff I loved about 3E. It's difficult to separate the actual qualities of the game from the surge of excitement and relief that came from knowing D&D was finally in experienced, enthusiastic hands and that the product they were turning out was of such high quality, but after playing it for so many years I think I can scratch up some objectivity.
Unified rules - I vividly remember sitting on the sofa reading the 3E PHB and wondering where all the stuff I knew from AD&D2e had gone. It took a tangible mental shift for me to grok what the designers of 3E had actually done and how it all fit together into more than just a jumble of systems that, in previous versions, had happened to work well as a game (or didn't, as the case may have been). If I ever have to reference a table to resolve a die roll, the game has failed in this respect. For a good, free-flowing session where the DM can adjudicate fairly and improvise smart rulings on the fly, the mechanics need to be intuitive and broadly applicable to a wide range of play.
The combat mini-game - 3E took the scraps of paper and d6's we used to scratch out combats at school and created a viable, grid-based combat mini-game that instantaneously enriched D&D sessions for my group.
It was possible to play the game without using the battle-mat, but tactical movement and positioning quickly became a guessing game if they even featured at all, and 3E combat as written just wasn't diverse enough to encourage tactical or strategic thought in an imagined space. At least, not for us. I'm sure others would disagree. It also spawned my temporary addiction to D&D miniatures, but I haven't bought any for years. Cured.
Presentation - OMG, those books were stunning. Amazing artwork, beautiful layouts, they just begged to be browsed and adored. And that was just the core three. When the first Forgotten Realms source-book came out I was rendered practically speechless. I bought it immediately, and I don't even DM FR. By the end of the 3E's run the design had become a little tired and over-used, but that shouldn't reflect on the impact of the originals. 4E majorly dropped the ball in this area, with text-book like tomes that were perhaps more usable at the table but utterly boring to read.
The Bad - By the time 4E was announced, I was sweating the problems with 3rd Edition and more than ready for a change. It's probably not a coincidence that the stuff I talk about below is the exact list of things I think 4E did the best.
Lack of interesting tools for the DM to challenge the players – This was the big one. It was partly due to my lack of skill at world building and encounter design in the 3E era, but as my long-running campaigns came to fruition and the PCs’ levels climbed into the mid-teens, I became increasingly frustrated at how the adventures gave almost total power to the players.
I consider it my job to challenge them, fairly and squarely, and I couldn’t do it without relying on insane save or die effects from over-stuffed spell-casters or one-off abilities dealing dozens of dice of damage to everything in the encounter. I despised this aspect of 3E, and watched it spread and infect all of the game systems to the point where almost anything cool or cinematic I tried would be immediately and calmly shot down by unperturbed players knocking the legs out from under the encounter with gleefully maximised characters.
I don’t blame the players for this. I want to be absolutely clear about that. They were certainly having a good time, but I'm sure they'd be the first to agree that they’re only one part of the equation. As the DM I need to be able express myself; I need to bring the drama, tension, and excitement forth from the campaign and give its encounters room to breathe. If not, why am I there? What job do I have if not that? Considering how many hours I put into preparing and running a session, I need to be more than just a dice robot. My inability to do this within the rules against well-built PC's sucked half the joy from many of my games.
When 4E came along, everything changed. Monsters had dependable, flexible, synergistic powers even at very low level and suddenly I didn’t mind spending hours thinking about a single encounter because very rarely would it be eviscerated by a save-or-die in the first round. Villains had actual strategic weaponry, built right onto their stat cards. Encounter building started to feel less like a desperate defensive action against the party's big guns and more like a troop deployment. You had to think like a commander...what would the vampire do? What minions would he summon to bolster his weak points? What did he know, or what could he find out, about the party's weaknesses? Terrain became integral. Encounters could be planned, paced and executed for maximum drama and coolness. Ah, l'amore.
4E mechanics had their problems, I'll be the first to admit it. Monster durability, the very thing that gave me freedom to plan dramatic encounters, could in the wrong hands become a tool for player boredom and frustration. Still, the only skill you needed to fix that problem was seeing the end of the encounter when it came...which was not necessarily--or even regularly--when all the monsters were dead or incapacitated.
I’ve taken two 4E campaigns into Paragon level and not once felt confounded or impotent because I just didn’t have the tools I needed to challenge the PC’s. The ebb and flow of a typical 4E hero encounter has become like an old friend. I’m nervous of a return to the Before Time.
Vancian spell-casting – Some might disagree with me here and argue that the classic “memorise your spells over breakfast” magic system is a staple of D&D and we can’t have one without the other. Well, to a certain extent I agree with that. Spell-books, spell slots, spell levels, and all that jazz were mostly absent from 4E and took some getting used to, especially as the grossly over-complicated and unnecessary replacement “choose 2 Dailies for every slot and pick one every morning” rule was so terrible.
As a caster-loving player of D&D, having to make those choices every morning and having to judge offence versus buff versus utility, based on whatever vague notion of that day’s exploits we had at the time, was almost always a pain in the ass. I understand that it introduced an inherent balance to overpowered casters, and I understand how careful parties could investigate and augur what was coming up to gain an advantage, but honestly I just felt hobbled in a way other players didn’t.
3E went some way towards fixing this problem, with open spell slots and swapped-out heals and so-on, but I still had to make those selections all the bloody time and very rarely put much thought into them. Plus, depending on your class, try convincing your Fighter buddy that you’re stepping out that day without Bull’s Strength or Entangling Roots or Mass Haste and see where it gets you.
Melee options – This was a weird one. On the face of it 3E offered melee combatants all kinds of options – Trip! Bull-rush! Grapple! – but in practice these options quickly became the purview of maximised builds, also becaming overpowered in the process. Your average warrior, who maybe didn’t want to spend half of his feats on a single schtick, was in no way capable of executing these manoeuvres against a level-appropriate foe, so the result? Options reduced to nothing. Get within reach, hit with weapon. Rinse, repeat. Bored. Bleh.
Monster and PC advancement using the same rules –So annoying! New monsters were often defeated before they even stepped off the page, because to make it good at this meant it had to be good at that which meant it needed to be of level x which was unfortunately five levels too high for your party and back to the drawing board. Arrrgghh!
Honestly, I often just ignored this bloody problem and fudged monsters behind the screen. I needed it to be better than the PC’s at jumping, so it was; I needed it to be able to see in magical darkness, so it did. That’s an entire design pillar of the game, ignored, because in practice it limited what I could create for my game. Some people loved this consistent framework, akin to the physical laws of the game to which everything must abide. Just look at any random anti-4E thread on your favourite RPG message-board and see how viciously the new game was knocked when the consistent framework was not only removed but thrown on the bonfire and set alight. I, however, do not want to see it back. It's a game, not a thought experiment.