Note: none of this shit will make much sense unless you read this and maybe this and are aware that the company that currently makes D&D has announced it will be releasing a new edition which will theoretically make everybody happy.
If this is all greek to you, just assume this is one of those "inside baseball" posts and move on.
Anyway, just to prove it could be done, in the posts linked above, I wrote up some rules that should approach making players interested in any previous edition basically happy (or at least able to talk to each other) possible.
-Grumpy Grognards:
Even if you never intend to buy a 5th edition written the way I outlined, the beautiful thing is, if one of your players does and then makes a character in 5e--you can run that brand new PC through any classic TSR module and s/he'll still fit. It scales fine. Bone Hill, Castle Amber, whatever.
-Here's a key concept I encoded in these rules:
People who want 4th edition-style powers and 3.5-style feats get them not by making their PC more badass than an Old School simple no-customization PC, but by trading away the default advantages of leveling up as a basic PC.
Like in order to get Whirling Blade Of Knives once per day upon reaching level 4, you have to trade away something a fighter would expect to get upon reaching level 4, like a +1 to fortitude save or to hit.
This combined with the principle that "monsters don't get bonuses to shit they aren't actually good at just for being high level" (giants don't get a reflex bonus) as sketched out here should result in a balanced game. Or at least a balanceable version of the game. No sweat.
-The differences between the kinds of adventures people expect in old editions and in 4th ed differ wildly, but these differences actually stem from very minor changes in the actual rules. Like I said before: you change the numbers----> changing the numbers makes the game more predictable---->making the game more predictable changes the playstyle.
-Therefore, the actual points of friction between the games are probably less than most people think.
-Good question: If Classic players aren't using powers, where do we put the powers? I think it should be a boxed set: Player's book, GM book, Powers & Spells book. Many superhero games back in the boxed set era were sold like that. Having powers & spells in their own book also just sorta makes sense at the table, that way at the end of the session when the thief and the wizard both level up, the thief can look in the PHB to buy new stuff while the wizard's looking up spells.
Also, the core books would only have a basic array of powers. There would be a ton more powers in a Tournament Players Supplement. PLUS there should be a simple math algorithm to convert existing 4e powers to Tournament 5e powers. At least until Wizards publishes new versions of them.
-Another thing: clever use of different fonts and graphic design should make it so it's really easy to tell which parts of a page are relevant to you.
There is a surprisingly vocal Oh No There Might Be Something On The Page Not Relevant To My Own Personal Game brigade. These people are kind of the mirror image of the people who complained that although I provided optional 4e stats in Vornheim I didn't put in monster "roles", and they get the same smack down: If you can't tell a flailceratops is a "brute" you should not be DMing, likewise if it distracts you that the word "(brute)" appears next to the word "flailceratops" in a monster description, you shouldn't be DMing. How the hell did you manage to ignore "Psionics: Nil" and "Treasure Type" and "No. Appearing" all those years in the AD&D Monster Manual?
-Healing surges:
I like this Wolverine alternative for Heroic and Tournament modes--instead of just having a bank of healing surges, basically in these modes, do this:
*When you first take more damage than you have hp, you are considered to be just "out of the fight" for a bit and no matter how much damage you took (unless you were like disintegrated) you're just at 0 hp. Not negative yet. You can, however be killed if folks keep whaling on you down to negative level (Heroic) or negative level + con (Tournament)
*Each round you can make a Con check. Success indicates you got 1 hp back.
*You have a choice then--spring up with your 1 hp and attack, or play possum, keep rolling, and pop up Wolverine-style after everyone's forgotten about you.
*However, as long as you play possum, you are still vulnerable to a death blow.
This makes healing a little easier to narrate plus adds a level of tactical complexity to using healing.
-Minions. In 4e you have dudes called "minions" who can be killed with one hit. Just change that to a rule that Tournament PCs can kill anything with one HD with one hit. Problem solved.
-If Tournament PCs start at 3rd level and Classic PCs start at 1st, how do tournament PCs fight goblins? Easy: 4e already constantly uses multiple versions of monsters--it already supports wimpy minion and dangerous levelled versions of the same monster.
-How will monster HD look in the Manual? Do this:
Ogre
4hd/38 hp
(Classic gamers use the first number, Heroic and Tournament use the second. 3.5 manuals already look like that).
(That 40 hp figure, by the way is derived from: 9hp per every 2 dice plus a +5 con bonus per die. Though you could do it however.)
-Saving throws are cake. Using an old product with a different saving throw regime than what you're using is pretty easy. Old editions reference a save table, you can just ignore that and use the new numbers whenever a monster appears. No matter what edition you are using, you can get a plausible Save DC for a spell by doing 10+caster level+caster int bonus. i.e. you can take a wizard or demon from a TSR module and have him cast a spell on a 3.5 style PC and the chance to avoid the spell would still make sense.
-What would a Monster Manual statblock look like?
Ogre (Brute)
AC: 16 (15 flat footed)
Hit points: 4hd/38 hp (bloodied 19)
Atk: +4 (to hit) 1d10+4 damage
________
(An experienced DM in any edition could stop here, and this is the amount of detail I recommend for passing references in modules--the rest of this info would go at the back of a module or in the margin)...
________
Fort: + 6
Reflex: - 2
Will: - 5
Level: 3
_________
(That's all the Classic DM needs)(at most)(there would be a line or a color change in the text at this point to signify that the basics are over)
_________
Dupe:-3
Notice: -1
_________
(Classic DMs might want to use Dupe (charisma and wisdom based) and Notice (wisdom and int based) modifiers even though they have no direct equivalent in older D&D. I know I would, but that's probably because I kinda invented them.
_________
Intiative: -2
Speed: 60'/round/6 squares
S: 19 D: 7 C:19 I: 6 W: 6 Ch: 4
+1 track +2 climb (any other skills an ogre might have)
(plus all the other crunch in a 3.5 statblock here)
_________
(That's all a Heroic DM needs, unless s/he wants to use powers)
_________
Then here is a pair of powers that can be traded out for a -1 to hit or damage minus each:
*Grab And Bite: 1/encounter. Successful hit on adjacent size M or smaller opponent inflicts d4 damage for a grab, then d10 for a bite and the opponent is considered grappled the next round.
*Toss: at-will. Successful hit knocks Size M opponent up to 40 feet/4squares doing 3d6 damage.
-Giving levels to a monster is easy under the system I've sketched out, by the way, a 9th level fighter bugbear could just add +9 to hit and +9 to damage and bam, there you go.
-4e's Action Points (which do mix things up a bit) can stay for Tournament PCs. And go for everybody else. In a Tournament fight you get them, in a different fight you don't
-"Classic PCs can, on a successful check, execute a combat maneuver, however, it should be noted that doing the same trick over and over is considered bad form."
-How does this benefit Classic edition players? Two ways:
*WOTC should be able to start publishing materials useful to them (and modules that are useful to more than one playstyle simultaneously) and
*by establishing a common language, DMs of different styles will be able to talk to each other more easily. Oh I run Heroic and I find... etc etc
-XP scheme the same as i wrote before:
Classic: XP is given for monsters and treasure. Treasure usually nets about 4 times as much xp as monsters required to get to said treasure.
Heroic: XP is given for monsters plus each PC picks what kind of thing they want to get xp for based on their PCs' individual motives. Like: "My wizard wants knowledge,""My paladin wants to help the weak" etc. The GM can award these as s/he sees fit but the total can still be divided equally if the PCs roll that way--so if everybody helps one PC achieve a goal, they all benefit
Tournament: XP for monsters at x5 normal.
Heroic: XP is given for monsters plus each PC picks what kind of thing they want to get xp for based on their PCs' individual motives. Like: "My wizard wants knowledge,""My paladin wants to help the weak" etc. The GM can award these as s/he sees fit but the total can still be divided equally if the PCs roll that way--so if everybody helps one PC achieve a goal, they all benefit
Tournament: XP for monsters at x5 normal.
-Switching styles: if the DM (or PCs) in a Tournament game would like to do a "quick combat" (initiative by side, no action points) then vote.
