The Core Mechanics offers up 10 House Rules to Make Grognards Like 4th Edition Dungeons & Dragons. Unfortunately, most of the house rules are of the Racing Stripes on a Yugo variety. (Or, if you’re a 4e fan, putting Fuzzy Dice and lowrider hydraulics on a Formula 1.) Except for Rule 7 (Don’t scale the Campaign Setting), they change the surface details like number of classes or races without getting at the essence of the play style. For instance, Rule 4: Limit Races to 3. White Box D&D from 1974 had the rule
There is no reason that players cannot be allowed to play as virtually anything, provided they begin relatively weak and work up to the top, i.e., a player wishing to be a Dragon would have to begin as let us say, a “young” one and progress upwards in the usual manner, steps being predetermined by the campaign referee.
So it’s not the Dragonborn that are keeping the Grognards away, ok? (Btw, just for comparison, that single rule is the same amount of space as devoted to Halflings, and only about a sentence or two shorter than the rules for Elves or Dwarves.)
So what would you really have to do to make 4e Grognard-friendly, assuming you wanted to? There are really three major things, and they’re comparatively simple, but profound.
First, you have to reverse the direction of causality in the system: cause and effect have to flow from the game-world to the rules, not from the rules to the game-world as it currently stands. What does that really mean for 4e? It means that you have to visualize what’s really going on in the world, and reason out the consequences from there. What 4e calls “the flavor text” is the power. You can’t just invoke “Tide of Iron” and move the mini, it actually has to make game-world sense that the character be able to push the opponent in that direction given everything you know about the combatants such as their relative mass, whether one of them is made of some substance that makes pushing/being pushed wierd or would have some other consequence–think about using your shield to shove a Gelatinous Cube around and you’ll see what I mean. And if the effect is not supposed to be magical, if you can’t explain how it would actually happen (frankly, most of the pull and slide powers) then you can’t do it. If the flavor text of the power causes small flames, that’s different from a power that creates icicles, even if the rules are otherwise identical. And just because two powers have rules that interact (the whole “exception-based design”) means nothing if it’s not clear how the interaction would play out/make any sense in the game-world. I expect that a lot of 4e players would balk at this, despite it being the same as Mike Mearls’ advice on running 4e without minis, but do you want to game with Grognards or don’t you?
The second thing you have to do is eliminate any vestiges of any rule or mechanic that can’t be understood in game world terms, and talked about in-character. That doesn’t mean that the characters have to use the exact same terms, but they have to be able to think about the concept. A Fighting Man might not actually say “Saving Throw”, but he could fully understand and discuss with the other characters that he’s much better at dodging a death ray or beam from a magic wand than he is at resisting a spell. He can talk about how hard it is to hurt or kill something, even if he doesn’t literally say AC or HP, and how experienced he is even if he doesn’t divide it into points of XP. For 4e that means dropping Skill Challenges. Sorry, but there’s no in-game way I can conceive of to explain the spooky action at a distance implied by the accumulating successes and failures (particularly the failures). You’re just going to have to do it the old-fashioned way, by reasoning about the logical consequences of each individual failure and success and whether there’s any causal reason one would influence the next. You also have to eliminate Action Points, possibly Healing Surges, and probably a raft of other things (“minions” for instance–a creature of the same type as another you’re fighting that can only take 1/100th or less damage can really put a dent in the old verisimilitude). You could try to “reify” them…make them actual things that the game-world inhabitants really do understand and talk about (perhaps with magical or divine explanations), but you risk turning your game into The Order of the Stick.
The final thing that you have to do, and this is really the culmination of the other two, is that you have to stop looking at the character sheet and the rulebooks to tell you whether you’re permitted to do something. If the player can describe the action in such a way that it makes a lick of sense in the game-world, the character can attempt it. The GM can assign a probability to whether it works (even if it’s so low as to be in effect impossible), or just rule directly, but everybody can attempt anything they can imagine unless it’s specifically called out as forbidden to their class (e.g. fighters learning spells, magic users wearing armor). Skills, feats, powers…they mean you’ve got a better shot, but the lack of one should never be cause for the GM to say no.
And that’s it. You don’t have to strip out the laughable names “Moon Prism Power Divine Strike!™” “Bloody-Riptooth All Cool And Spiky Badass MoFo Crocodile™.” You don’t have to put save-or-die effects in, enforce completely random chargen, have level-draining undead, or make magic Vancian. All of those things were indeed common enough back in the day…but they weren’t the essence of game-play; plenty of undeniably old-school games didn’t have those features….even if they were using a system that did (3d6 in order was one of the first things that many groups discarded; by the time of Basic D&D there were official, if optional, rules for discarding characters with no score above 9, or swapping attributes). You could add one or more of those, but the plain truth is that the Grognards who would insist on them aren’t likely to touch even a revamped 4e with the proverbial 10′ pole, and those are the things that 4e players are most likely to strongly object to. On the other side, I think that many of the things that are show-stoppers for the Grognards literally fall beneath the 4e fans’ notice….in prior conversations trying to explain the differences I get the distinct impression that they don’t even realize (and some don’t believe) that these actually are differences between the way the editions work, or they discuss them solely in terms of design goals (this is faster, everything you need to know is written on this card) without even considering whether it has implications for how you think about the world.
So on the one hand, I do actually think a 4e for Grognards is possible…in some sense even easy: just ignore a bunch of these rules, and interpret these ones in a different light. On the other, I’m not entirely sure whether the result would be still be 4e.