With advent of 4th Edition, and my general unenthusiastic response to it, I have come to a conclusion: there's not a single edition of D&D in all its forms that suits me perfectly.
I like the stream-lined core rules of 3rd Edition, but dislike all of the fiddly bits and the ridiculous prep-time for DMs. AD&D (both 1st and 2nd Edition) have my favourite flavour and rules effects (i.e. what the rules are trying to do), but are a bit too random in the implementation of those rules for my tastes. The various forms of Basic are great to play out of the box, but a bit lacking in complexity, especially for PCs. And OD&D is a great free-wheeling system, but it's a little too vague. 4e has a few nuggets I like bolted onto a system that's only barely recognisable as D&D. So what's a dedicated role-player who loves to kill orcs supposed to do in this situation?
There's only one thing to do: roll up my sleeves and write a version of D&D that perfectly fits my taste. I'll be calling it D&D Nth Edition - N for my first name, and N also for the mathematical representation of infinity, as I intend this to the be-all and end-all of D&D for me (apart from my Project of Insanity, which you can read about lower down).
The basic goal of my version of D&D will be this - take the way the rules work in older version of D&D, express them in ways more familiar to modern games, and sprinkle with touches of things that I like from all manner of D&D version and derivative games.
Here are some examples of my thinking on how to improve some of the major elements of the game:
ABILITY SCORES: I won't be changing much here, as the classic six abilities are about the only thing that have remained unchanged from edition to edition. I won't be using the Devil's Tool that is point buy, but I also won't be requiring players to roll 3d6 in order. I'm thinking that 4d6, drop the lowest roll and arrange to taste is where it's at, as that's how I've done things for many years.
As for the various modifiers, I'll be going for something that looks like the unified progression of 3e. I don't want the modifiers to scale quite so high, though, so the bonuses might begin at 14 instead of 12. I also have a problem with the way the modifiers scale downwards - it's easy to model very strong creatures, for instance, but very weak creatures can only go so far down.
RACES: I'll certainly be including the big four: Men, Elves, Dwarves, and Halflings/Hobbits. Half-Orcs I believe also have a niche. Gnomes I'm not so certain about - they're far too similar to Dwarves, and I don't believe that as written they're needed in the game. I need to give them some more thought.
CLASSES: For the moment I'm going to focus on the main four classes - Fighter, Cleric, Magic-User and Thief. Once these guys work, it's time to start thinking about the various sub-classes. But I expect that they'll look much like the classes from 2nd Edition, just with a rules set that looks more like 3e.
SKILLS: I do believe that D&D works better with a skill system in place, but I think the one in 3e is much too fiddly. I toying with the idea of including a list of common skill usages, and a universal chart that maps difficulty to a specific DC - so if something is easy, the DC will be 10 regardless of what skill you are using.
As for choosing skills, I'm tempted to make this function of class and background. Say your character is a Thief who grew up in the circus - he'll be good at all of the regular Thief-type skills, and he'll also know juggling and acrobatics and a bit of animal handling. I prefer it to be a bit more vague and loose. Also, skills won't be scaling up with level - characters will get their Ability bonus, another bonus if they have an aptitude with the skill, and that's that. I might also include a mechanic for training your skills up, but that's also something I need to think about a bit more.
FEATS: In more general terms, I think a degree of character customizability is desirable. Whether it's through a feat system similar to 3e, a power system like 4e, or even Skills and Powers from 2e I haven't decided yet. What I want to avoid is creating a system that discourages using certain tactics if you don't have the relevant feat.
COMBAT: Now, this is something I want to scale back in terms of complexity. 3e combat takes too long, and 4e doesn't look to me to be an improvement on that score. One thing I want to provide is a list of common combat maneuvers, such as a stunning attack or trip or disarm. Things like that are in 3e, but I want to simplify them massively. And feats will enhance these options rather than making them available, because anyone will be able to try this stuff.
MAGIC: Vancian magic stays, because it's part of the essence of D&D. I'm definitely going to rejig the spell levels so that they match with class level - for instance, Fireball will be a 5th level M-U spell rather than 3rd. This won't affect anything mechanically, but to me it seems a lot more intuitive to teach people.
Also, I want to take the spells back to how they worked in earlier editions. Sleep spells with no save, polymorph causing a chance of instant death, raise dead making you lose a point of Constitution, that sort of thing. Many of the problematic spells in 3e had drawbacks in earlier editions - 3e took them out and caused itself a lot of problems.
MONSTERS: Simplify! Simplify! If I can't get these things into two line stat block, I haven't done a good enough job. I plan to go through the various editions and try to boil each monster down to the most interesting and iconic abilities. I might also steal a bit from 4e in this regard, because it does do a lot to make the humanoid races a bit more mechanically interesting.
And that's a general look at my thoughts on this for the moment. I have a lot of other minor things I'm toying with, but I'll be talking about those in later updates, when I can zoom in more on the specifics.