D&D 5E Should the splatbooks to come be theme-based or class/race based?

I think I'd rather avoid the whole notion of splatbooks alltogether.

Setting books, fine. Adventures, great.

But when it comes to offering new options... I feel like these sorts of things should be presented in additional DMGs, right? I mean, the DMG is being pitched as the DM's modular toolbox and workshop... I feel additional class options ought to follow the same template.

It also shifts player/DM interactions. Instead of the player feeling entitled to the new hotness since he went out and gave Wizards $35 for their new book, it's now perceived as the DM's prerogative to peruse additional material and make some of it available to his players if he feels it fits the campaign.

And it changes the goal for content authors. Instead of marketing their new stuff to players, where power creep is rewarded with huge sales (and the DMs feel pressured into letting their players use it), marketing new content to DMs is more likely to incentivize writing interesting stuff that fills unexplored niches and creative approaches to mechanics.

Which seems to fit way better with the modular approach that really has me interested in 5E.

My biggest request is for them to be good and not trash. The 3e era was just terrible and despite it's attempt to, I don't think it was much improvement over 2e. It just felt like they were writing anything to fill the book so they could sell it. I skipped the 4e era, but I doubt it was better.

The only pure splatbook I ever want to see is psionics.

I do not want to see splatbooks that tinker with existing classes or categories of classes, ever.

If they want to add a bit of setting-specific splat into the fluff material for a given setting, that's fine, but it should be kept to a minimum. Add only what's absolutely necessary.

That said, I'm hoping the core rulebooks give ample guidelines for things like designing your own cleric domain or wizard spell. Stuff that is already baked into the game, not completely outside-the-box game design territory like completely new class features.

1. Splat books are fun, but only if they don't suck. I personally see room for more subclasses in the phb classes.

2. Separate DM and player materials for settings is really important to me, for the sake of avoiding spoilers. It wasn't until 4e that someone realized they probably shouldn't mention world-changing secrets in the player's guide to Eberron (and yes, it does matter. My players still dont know half the secrets).

Mike Mearls has been pretty clear that he doesn't want to do splatbooks. I'll see if I can find some quotes.

I think this is the right approach. I would much rather see WoTC focus on campaign setting books and adventures.