Although White Wolf turned the splatbook into a central plank of their 1990s business model, they weren’t the first major RPG publisher to hit on the idea of pushing products aimed specifically at players rather than GMs, each themed around a different type of player character. That accolade goes to TSR, who followed up the publication of AD&D 2E’s core books with a series of class-focused books with chocolatey-brown cover art, with the line soon branching out into race-specific books as well as more offbeat entries like The Complete Psionics Handbook and The Complete Book of Humanoids.
The idea of selling books of player-facing material divided by class was in principle a good way to meet demand and to produce products which, whilst designed for 2E, were compatible enough with 1E and added enough that was novel that you could still sell the books to people who hadn’t migrated from the earlier edition. The downfall of the line is that there doesn’t seem to have been much oversight and cross-product co-ordination, with the result that some splatbooks ended up adding more power creep than others. In addition, some of the books seem to have struggled to come up with sufficient material to meet the page count – they often resort to sections of variable length on generic roleplaying advice dressed up as advice on roleplaying the classes in question but frequently amounting to universal platitudes, for instance.
The Complete Fighter’s Handbook, for instance, pads itself out with some extra weapons and a lot of waffle about investing your sword-swinger with a personality, whereas the Thief’s Handbook includes a bunch of waffle about how Thieves’ Guilds are run which is sometimes interesting but should probably be referee-facing, and the Priest’s Handbook incorporates rules for designing religions and cosmologies which should definitely be for DMs to use rather than players under most circumstances. The Wizard’s Handbook, however, commits the ultimate sin of presenting a player-facing supplement: throwing out a bunch of new spells which a referee may or may not be happy with including in their campaign, but which by being put into a player-facing supplement creates an expectation that if a player’s spent their money on the book the referee should at least consider including the stuff – beginning the tendency towards bloat that many complained bitterly about during the 3E era.
One common strand among the class and race handbooks is the inclusion of kits, which provide a new aesthetic skin, a bundle of proficiencies, and some special bonuses and weaknesses for your character class. This is one solution to the age-old problem of members of classes tending to feel alike, but a problem soon becomes evident when you compare them from book to book – the kits range from desperate scraping of the bottom of a barrel (is there any reason a jester should be that different from a regular bard?) or riffing on the same general theme from book to book. (For instance, lots of classes have an amazon-themed kit, a peasant kit, an aristocratic kit and so on.)
Ultimately, I think 5E Backgrounds are much better and more elegant solution to the same general problem, and they have the advantage of not being arbitrarily divided up by class in a bid to fill out splatbooks. And that’s really the main barrier to me embracing a take on 2E that incorporates all of these splatbooks; to get the best out of them you really want to use kits and proficiencies, but 5E covers all the same bases those subsystems cover in a much more robust and adaptable way; were I to play or run 2E these days, I’d advocate for trimming back most of the optional rules, which would make this line rather useless.