In the 3E days I did start dipping my toe in the water. I picked up a few 3pp books because I found them very very cheap on ebay ($8) or at the local store ($5-10). I only actively sought out 1 though (Seafarers Handbook) and impulse bought another one (d20 Dragonlords of Melinbone PoS book). I bought maybe 8 3pp books during 3E which was around 10%. At the time I did not regard Dragon and Dungeon magazine as 3pp as such it was a licensed product (2pp?) and to me it was just Dragon and Dungeon I did not care to much who made it.
I have a number of Sword & Sorcery books: Relics & Rituals and Creature Collection one and two. All unused, all useless.
I must have purchased them so early in the 3E era I had not yet understood the dangers of unbalanced content made by people other than the edition's designers.
Of course, this doesn't mean WotC is immune. Late 3E books were just as ill-advised.
The reality is that the things in an edition I truly gain value from are
early core books made
in-house.
Early = books published so early in the edition's run, they get used by the official adventure modules (the future Curses of Strahd and Storm King Thunders). I sincerely hope Volo's will be considered "core", since if it's just offered as options for DM's it won't be nearly as useful to me.
Core = It would be a shame if the core three books will remain the only content that adventure authors can draw from and reference. Why? Because for all the generous race options in the PHB, the spell chapter is far from complete.
But that's probably the least pressing issue, since any adventure can probably just make up or wing a special magic effect. More problematic is the selection of magic items (in the DMG). Up until Storm King's Thunder, using the random tables is probably fine. But now that has been done. The next time an adventure goes for random tables, it better be an adventure with a sizeable new magic item appendix. Or better yet; that there is a new book with magic items that is added to core so future adventures can reference it. (Or best of all, that this new book republishes all the items of the DMG. After all, as an experienced DM the items are about the only thing I really need the DMG for. It would be a great boon if magic items came in a book of its own, so I didn't have to get the DMG at all)
But if there is a truly weak spot of this edition, it is the Monster Manual. There simply aren't nearly enough mid-CR monsters and almost no high-CR bulk monsters. (That is, almost all high-CR monster is a boss monster rather than the rank and file monsters a high-level campaign needs). And I need more NPC stat blocks. Let me clarify that: I need more NPC stat blocks for adventure authors to use, so they don't have to make every elite guard a Veteran.
In short, if I look back on my 3E library, I realize that offshoot items such as Ghostwalk or Arcana Unearthed or Relics & Rituals simply never gets used.
In-House = There simply is a layer of sheer quality when the game's designers are involved that seldom or never are matched by third-party fans (whether professional publishers or idealistic fans). 5th edition is very tricky to get just right. I have looked at a few things over at the DMs Guild, and most of it is... off somehow.
I know this isn't what WotC needs to hear, but what I want them to publish is:
*** The PHB and a DMG without magic items (that I can skip).
This edition's PHB is the most generous ever, and while I won't complain, I could definitely have lived with a leaner approach (that ruthlessly postponed any class not of highest quality), if a PHB2 would be considered core.
Races are cheap (they're easy to make and it's hard to unbalance them) while classes are hard. So the generous race selection isn't really that generous. That the 5E PHB contained a few classes too many is something I think we can all agree on - they could not give them all the quality they need and deserve.
What I'm fishing for is that a generous PHB1 means a PHB2 can be postponed. The need for a PHB2 would have been much more pressing if the PHB1 left out a few iconic choices. I think 4E arrived at a good balance here; its PHB2 arrived early enough and contained choices interesting enough for the combined selection to really make its mark on the edition.
*** At least two Monster Manuals in rather quick succession so both are available for the bulk of the edition's lifetime. Focusing on low-level critters in MM1 is fine
if a MM2 is specifically included into core. If only the first Monster Manual is to be core, it really needs to be much more comprehensive than the 5E one, with a much meatier focus on CR 5, CR 10 and even CR 15 "trash mobs".
(This is partly borne out of my resignation that a single MM would have to be absurdly thick to cover all our basic needs. So it's not that I want to split it into two books. I just accept it has to be this way, and move on to actually getting the second half sooner)
*** At least one Magic Items Guide, complete with rational creation and pricing guidelines. If this was a stand-alone book, it would probably be able to cover the major omissions from the 5E book. (That is, a book of the DMG's size could cover a lot of ground if all the newbie faff about creating campaigns, running adventures and creating random dungeons were ripped out). Essentially, split the book so one book contains contains treasure and "Dungeon Master's Workshop" and the other contains all the rest.
*** Adventure campaigns. I'm actually rather pleased with WotC's approach this edition. Sure I'd like one or two additional supplements featuring half a dozen stand-alone adventures to complement the monolithic campaigns, but still.
*** Then after this the usefulness of any additional module sharply falls off.
Sure I found
Magic of Faerun very useful back in 3E, since it contained not only spells (most of which were about as useless as the EEPC ones) but useful trinkets like the equivalent of the 5E Svirfneblin Spell Gems (from the Out of the Abyss). You might not.
Some of you might find a Psionics supplement absolutely necessary. Myself, I'm not so sure - so far no edition's attempt has managed to walk the fine line between uselessness and overpoweredness... while still making psionics unique and something other than thinly veiled spells.
Point is not to squabble over which additional module to publish. Point is: none of them would have nearly the same universal usefulness as the ones above.
