I rather hope 5e is not currently in the works. Just after 4e hit, The Rouse commented that he felt 8 years was about right for an edition cycle, and I generally agree with that. Also, if they're doing a new edition, it must surely be in an attempt to reclaim the 'lost' players (to PF, 3.5e, or the OSR), but to do that in large numbers will require a significantly different game, meaning the DDI will pretty much have to be thrown out and started
again.
Now, all that said, as a thought experiment...
First, some philosophical positions:
- The game must not require miniatures. In fact, it must not 'require' them even in the same way 3e/4e/PF 'requires' them. (That is, you can play without, but...) However, if the game can be set up so that it benefits from the use of minis, all the better.
- The game must not require any electronic component. Again, it must not 'require' one in the same way that 4e-with-all-the-supplements 'requires' the CB to keep it straight. (Again, you can play without, but...) If the game can be set up so that it benefits from the use of the DDI, all the better.
- The game must not require (or 'require') any collectable component. Again, if it can be constructed so that it benefits from one...
- The bulk of the money is in the electronic form. Therefore, the main purpose of physical products is to get people playing, then (hopefully) transition them to DDI subscribers.
- That said, some products are vital to the existence of the game, and therefore must be done even if they lose money. This
may include all physical products; it
certainly includes adventures.
- It's easy to release products to add complexity to the game; it's nigh-impossible to release a product that removes it. Therefore, your entry point needs to be the simplest possible expression of the game.
- If you can't do something well, it's better not to bother doing it at all. Even the most ardent DDI-booster really has to admit that all is not right there at the moment, and that is just wrong.
Physical Products
Crunch-books
The major change I would make would be to kill off the "3-book" sacred cow. The game should operate out of
one Core Rulebook, that actually would be very similar to the Essentials "Rules Compendium" in format - smaller size, paperback, and no more than about 250 pages.
Said book should contain rules for 4 races (human, elf, dwarf, halfling), 4 classes (fighter, wizard, cleric, rogue), the Heroic tier, a basic set of magic items, a basic set of monsters, and guidelines for the DM running games in that tier.
On Day One I would release two products. The first of these would be the "Basic Set" - the assumed starting point for all new players in the game. This would be quite similar to "Wrath of Ashardalon" in terms of price point and content - it would contain a quick-start guide, pregenerated characters, dungeon tiles, minis, dice, a pencil, an adventure book... The two key additions from WoA would be the addition of the Core Rulebook, and an expansion CD.
(The expansion CD would contain further adventures, a stripped-down Character Builder tool, sample issues of eDragon and eDungeon, and a link to the WotC website (with a nice handy "subscribe to DDI" link...))
The other product would be the Core Rulebook, sold separately. This would be aimed at experienced players, who probably don't want all the bells-and-whistles.
Shortly after Day One, I would release most of the other components of the BS as separate purchases, but this would definitely be later to avoid confusion.
Also, note:
it would be the same Core Rulebook in the Basic Set as everyone else uses.
Over the next year, I would release a "second circle" of books, expanding the game out to provide all the classic races and classes, more monsters, more powers, and the full level range. I would probably do this with five additional books: an "Advanced Player's Handbook", an "Advanced Dungeon Master's Guide", a two-volume "Bestiary", a "Grimoire" (or similar... or maybe not), and a "Tome of Treasures".
These would be designed assuming that they are used along with the Core Rulebook, and that they're used as a set - the APH can safely refer to the Grimoire, for example.
This would be the 'complete' game for the more hardcore gamers.
Finally, for the truly hardcore, I would probably do a "third circle" of books, being the splatbooks classes and races, and the like. That said, if the splatbooks just look like "* Power" for 4e (that is, little more than just a set of powers), then these are better released in card format.
At the same time, I would support the Basic Set with an Expansion Set a year later. This would assume only the use of the BS, and would include more of the same - more pregens, more adventures, more tiles, more minis. Basically, just provide more for the more casual gamer.
Settings
The 4e model of three books is probably about right, to be honest. I would let the Forgotten Realms lie fallow for a good number of years (possible reboot with 6e?). Unfortunately, that does leave a hole - neither Eberron nor Dark Sun is really vanilla enough to be the 'featured' setting of the edition.
I'd probably just stick with the 4e PoL implied setting as far as possible. Maybe do a couple of mostly-generic area supplements...
Adventures
Again, I think the volume and format of 4e adventures is actually about right. A couple of things I'd change, though...
Firstly, the Delve Format would mostly be gone. This allows the writer to pack more adventure into a smaller space, and probably allows a bit more freedom in adventure design.
Secondly, the adventures would be strictly standalone - there would be no equivalent of the HPE1-3 Adventure Path in print.
One other product I would do would be an annual "Dungeon Delves" product - a book containing about a dozen or so short zero-prep adventures (done in the Delve Format), intended for play in a single evening. This would be aimed at the harried DM who needs something to run in a hurry.
And that's it for physical product...
Electronic Support
While it should not be
required, the aim should be that the DDI should be so good as to be considered a "must have" accessory for the game.
I would introduce a three-tier pricing structure for the DDI. (Note: the following talks about 'players' and 'DMs' getting access to different things. That's just for ease of reading; in fact, all subscribers at a given tier would get all the appropriate things listed.)
At the
Bronze tier, players would get access to the Character Builder and the Compendium. DMs would get access to the Monster Builder. (All these tools are familiar to us!)
At the
Silver tier, players would get access to eDragon. DMs would get access to eDungeon, and the Adventure Builder and Campaign Builder tools. (See below...) And all subscribers would get access to the Virtual Tabletop.
At the
Gold tier, DMs would get access to The Vault.
Some explanation about the various things:
eDragon would be a monthly magazine, much as you might expect. I would move the format
a lot closer to the late-Paizo printed product, right down to a fixed monthly release date for
all material.
eDungeon would likewise be a monthly magazine, and would likewise have the fixed monthly release date. The ideal format would have
five adventures every month: two zero-prep delves and three longer adventures (one for each tier). Of the three longer adventures, one should be standalone and setting-neutral, one should be standalone and tied to a specific setting, and one should be an Adventure Path module. (There should be one AP per year, probably running for 15 levels in 9 installments.)
eDungeon should also feature lots of 'how to' articles, walking through adventure and campaign creation, map making, and so on. Finally, it should feature to development of a DDI-exclusive setting that subscribers can directly influence as it is created.
The Compendium is as it is now. Notably, this will be the easiest way to "catch them all" as regards the collectable power cards (the replacement to "* Power" discussed above).
The Adventure Builder and Campaign Builder tools are as the name implies - easy tools to create elements for the game. At the Silver tier, these would have limited functionality - the ability to manipulate only pre-generated elements (Dungeon tiles, etc). At the Gold tier, they would allow users to create their own custom elements.
Crucially, whenever a custom element is generated (whether this is 'just' a tile, or a full-blown adventure, campaign, or world), the creator will have the option of adding it to The Vault.
The Vault would be a repository of the collected genius of all DDI contributors (including exclusive content from the designers, of course!). It's the OGL again, but controlled by WotC. I can see that being a huge time-saver - instead of having to create whole new adventures/campaigns/maps/whatever, I can just pick the brains of the best of prior art.
(If I could see a way to make it work, I would like to offer some incentive to DMs who add to The Vault, or indeed those who run games on the VTT - some minor discount on their renewal, or periodic contests to showcase the best and see themselves in print, or something. But, as I said, I suspect that may be impractical.)
Mechanics
As noted above, the core ruleset should be vastly simplified from its current position. I have no problem with adding complexity later, but the core should be as easy as possible.
In fact, much of 4e is pretty much okay - there are some changes I'd make here and there, but I suspect many of them would merely be
different, not necessarily
better.
A couple of things I would definitely do, though:
Firstly, ramp the power level of 1st level characters back a bit. Ideally, the first level character should be the equivalent of elite mercenaries (or real-world Special Forces) - they're clearly a cut above the norm, but they're not outright superhuman (as is the case now).
In fact, if DC 30 represents to pinnacle of real-world human achievement (the point at which World Records fall), then I would suggest that optimised PCs should start to be able to hit that around 8th level (not quite the end of the Heroic tier).
(Note that real-world World Record holders are insanely specialised; even the most optimised PC is necessarily more well-rounded than that!)
Secondly, make a much clearer statement of what the tiers are supposed to represent. I would argue that Heroic adventures should be mostly human-scale, Paragon adventures should be larger-than-life but not absurdly so, and Epic adventures should be the truly world-shaking stuff.
(Heroic PCs are the Black Company or the Three Musketeers; Paragon PCs are Aragorn or the Knights of the Round Table; Epic PCs are Achillies or Leonidas. (Note that none of these examples feature heavy magic use - scale the magic appropriately.))
Thirdly, I would reduce the number of independent things that make up a PC. Largely, I would do this by removing ability score increases by level (or, actually, any other source), making feats small, discrete "always on" numerical bonuses (meaning that the Core Rulebook could conceivably include
all the feats in the game!), and so on. Conversely, things like a character's powers or magic items should expand the range of "what the character can do" (maybe giving temporary and situational bonuses).
(To give some 3e examples: Skill Focus should remain a feat; Cleave should become a power. Toughness is a feat; Improved Counterspell is a power.)
Fourth, I'd further simplify monster design to facilitate rapid prototyping.
Frankly, in actual play players are unlikely to notice the difference between the Orc having a +1 to hit and it having +2 to hit (chances are the DM will miscalculate at some point in the encounter anyway

). So, set all monster attack/skill modifiers to multiples of +5, and all defences to multiples of 5. (Enough so that players
will notice the difference. Also, set all damage values to either Xd6 (no modifiers) or to 1d6+modifier.
(Under this paradigm, monsters are distinguished from one another primarily by "what they can do" - that is, by their powers.)
I've gone on too long.

Hopefully, that gives some feel for what my thoughts are at this time.
