I'm kinda glad WotC is taking it slow with 5E releases. In my case I'm unlikely to buy much "splatbook" type of stuff anyway - I'm fine with having just the core three books and creating my own new material or adapting stuff from older editions, if I ever run 5E. Some updated setting books (anything but Forgotten Realms please!) would be nice though. By the way, some 3rd party publishers have been creating stuff for 5E, despite not having an OGL.
I've never found splatbooks to improve the game in the long run -- at least the generic ones. Quite the opposite, in fact.
Setting-specific character options are (or can be) great and can really make a setting feel distinct (defiling in Dark Sun, Dragonmarks in Eberron, etc). The same goes for books focused on a particular campaign theme but not tied to a specific setting (e.g. pirates & seafaring adventures, horror, war, "oriental" adventures, swashbuckling, etc).
It's the kitchen-sink splatbooks that I hate, for the most part.
PHBR1 The Complete Fighter's Handbook was pretty cool back in the day, as it included a lot of stuff that made combat more interesting. There was some good info on running a fighter-oriented campaign. The "character kits" section wasn't really the focus of the book, but this was where the decline started. None of the kits in this book were overpowered, but this was where the thematically incoherent mess of kitchen-sink D&D really took hold. The classes in the 1e and 2e Player's Handbooks were designed to work together and fit the pseudo-medieval-European milieu reasonably well (if you didn't think about it too much). Then the
The Complete Fighter's Handbook shows up, followed quickly by the books for Thieves, Priests, and Wizards, and of course players want to try out everything in the books. So now the campaign starts out like the set up for a bad joke:
So, a Samurai, an Amazon, a Pirate, a Pacifist Priest, a Witch, and an Acrobat walk into a bar...
Never mind that it was an elven Samurai, a halfling Amazon, a dwarf Pirate...
Some of the kits in those first four books were clearly better than others, and virtually everything in
The Complete Priest's Handbook was severely underpowered compared to the basic cleric, but I remember them as being mostly added flavor and nothing grossly overpowered or game-breaking. Then came
PHBR5 Elves Are Better Than Everyone Else and Don't Need to Sleep, Eat, Fart, or Even Take a Shit and set splatbooks upon their future path.
3e fared no better. Prestige classes sounded like a cool idea at first, representing more advanced career paths or setting-specific organizations, but the first splatbook (
Sword and Fist) alone shit all over that concept. Sure, the Weapon Focus and Weapon Specialization feats represent a fighter who has dedicated his life to mastering a particular weapon, but here are some 10-level classes for warriors who want to
totally master a particular weapon. And a special class for warriors who master spiked chains, just because. Oh, and there's a couple of weird monk classes because this book says it's for fighters
and monks and we haven't written anything for them yet.
Organizing additional character options in books centered around game mechanics like classes or races is just a bad way to do it. You'll either end up with a thematically incoherent campaign or a stack of books where you only use 4 pages from each one. Also, by the time every class book has come out, power creep has likely made the options in the earlier books less appealing. This happened in 2e, 3e, 3.5, and 4e, and I am certain that it would happen in 5e as well.
Some degree of power creep is inevitable when you start publishing new character options, but if they are only published as campaign-specific material for the entire set of classes, then it really doesn't matter so much if 5e
Oriental Adventures options are less powerful than the 5e
Fine, Here's Planescape, Now Stop Bugging Us options published 3 years later.
I would, however, be willing to accept an eventual book of new "general" character options akin to the 1e
Unearthed Arcana book, provided that the material was actually balanced and thoroughly playtested. Oh, and that the book's binding wouldn't fall apart when you breathe on it. But I'm talking about one book expanding the non-campaign-specific options for all character classes. I absolutely do not want to see any class- or race- focused books. Those types of books start the inevitable countdown to the new edition that is required to clean up the mess.
Also the sad fact is, PnP D&D will always be just a side-project in Hasbro / WotC's eyes, compared to the video game licensed projects and Magic.
This is both good and bad. On the plus side, it means that they are less likely to meddle with it too much or impose stupid "business models" on it.
D&D is a pretty complete game with just the core rulebooks and doesn't really need any additional rules. The game has actually always done very well when there was a small set of core rules and some adventures to play. Aggressive release schedules have generally not been a positive indicator of the game's health. The early years (1974-1979) and what many would consider the "golden age" when D&D was at its peak as a cultural phenomenon (1980-1984) saw tremendous growth in the popularity of the game, but a fairly controlled increase in the number of products being produced each year. And the product line was heavily weighted towards adventure modules, rather than rules expansions and campaign settings.
From 1985-1988, TSR's focus shifted towards additional rulebooks and campaign settings/supplements, culminating in a reboot of everything in 1989 with AD&D 2nd Edition. Even before the
Player's Handbook hit store shelves,
The Complete Fighter's Handbook and
The Complete Thief's Handbook were listed in that year's TSR Product Catalog. What followed over the next six years was an absolute glut of product.
Fifteen books in that PHBR series.
Ten campaign settings with their own product lines, two of which had at least one sub-line. Some of this stuff is destined to sit in a landfill next to E.T. cartridges. TSR was a train wreck waiting to happen throughout the 90s, until it finally did happen in 1996.
3e was a massive hit at first and seemed to bring in a lot of new blood, yet within 3 years the game was rebooted with a revised edition. The quality of WotC 3e supplements was rather poor, and there was an avalanche of 3rd party product that displayed an appalling lack of quality. Within four years, there had been enough hardcovers produced for 3.5 to fill up the back of a pickup truck, and 4e was announced. The hardcovers for 4e were released at an even faster rate than they were for 3.5, and it was only two years before the line was NOT REBOOTED, HONEST with D&D Essentials. Not even two years later, they were talking about the upcoming 5e playtest.
Now many things are different in the 2010s compared to the 1980s. What I've talked about above is just circumstantial evidence, and there were obviously many causal factors at play. There are certainly other reasons as to why each successive edition has a shorter lifespan than the last.
But maybe, just maybe, the "huge variety of options" doesn't actually increase the lifespan of the game by offering players enough variety that they don't get bored as quickly. Maybe all of these options just end up contributing to player burnout. Too many products to buy, too many books to cart around, and too many decisions to have to make when starting campaigns, creating characters, or even just going up a level. Players get tired of buying books with cool options only for the DM to say "no, that doesn't fit my campaign," DMs get tired of having to say "no" all of the time, DMs get tired of having to get familiar with the new material that players bring into the campaign... After a while, the appeal of switching to a different game that uses 1 or 2 books becomes pretty tempting.
I'm not saying this is the case with all, or even most, players. I'm just musing.
Given the history of the game, I think that this slow rollout is probably a good thing. They'll lose some players who want a robust product line and a suitcase full of books with character building options (they already have Pathfinder). But they could very well lose more players and kill the game's positive momentum by releasing too much too soon. We're just now at 8 months from the release of the last of the 3 core books. I would much rather have a lean first year after the core books so that they have a chance to gather feedback on the finished product than get 3 or 4 books that were largely developed before the core rules were finalized.