I thought the rumor/speculation was for a First World book? Giants, primordials, and dinosaurs would certainly fit in that sort of setting very well.
Agreed. I believe that this is the most likely option. We already have lore for Giants in Volo's (yes, it's being discontinued digitally, but we don't know if they're doing that physically), and there just aren't enough Giants in the history of D&D to justify a book like Fizban's for Giants.
I think forum users are overreaching on the First World angle. It's not set up in Fizban's as a Setting, but as a Platonic realm of Ideas that explains why different D&D worlds share so much in common.
This feels much more like Fizban's with giants, particularly given Wyatt's invovlement.
Fizban's, the book made primarily by James Wyatt, was also the book that introduced most of what we know about the First World. And, in case you haven't seen the interviews with him about the book, he seemed really excited about the concept and talked about it for quite some time.
If they are doing a Fizban's style book for Giants of the Multiverse, the player stuff from SKT seems likely to be reprinted.
There was no "player stuff" in Storm King's Thunder, unless you count the magic items. No races, no backgrounds, no subclasses. What are you referring to?
I am very much not a fan of a new setting designed to rewrite the origins of all previous settings (likely as an attempt to strengthen branding).
It doesn't matter. It matters just as little as the fact that Eberron exists in the Great Wheel matters. It's completely useless to the people that don't use it and can be ignored extremely easily, and it's a great concept giving quite a lot of people exactly what they wanted for the rest.
Whether or not the First World actually existed is up for debate both in setting and in the real world, and even if it's confirmed that it did, it doesn't matter to the rest of the D&D Multiverse except to explain a few meta-questions (why so many of the same creatures appear in very different settings).
They published Eberron decades ago, back when they a few shreds of creativity left (at least enough to recognize Keith Baker had a salable idea). No way would something like that pass muster today.
What new ideas? Streamlining and removing/altering content to conform to shifting social mores is not innovation. The only thing even close is the feat/background combo they've been experimenting with in UA, and that's nothing new to 5e, just to WotC.
Did you miss 4e, or are you purposefully ignoring Nentir Vale/Nerath? The World Axis Cosmology is still very popular, even though it's not the base cosmology of 5e. Some of its planes (Feywild and Shadowfell) were even integrated into the Great Wheel due to how popular they were.
Or Fizban's, where they completely reinvented the concept of Great Wyrm dragons to make them more than just "Bigger Ancient Dragons", and introduced the idea of the First World, and introduced quite a few new monsters, too. Or the several new adventures that they've come up with since 5e's start (a lot of them are pretty bad, but there's still a lot of creative/inventive stuff in them).
Wtf does "creativity" mean to you? Does it exclusively mean "the ability to make new D&D settings" while excluding the fact that they were the ones that created Nentir Vale, the Feywild and Shadowfell, and have announced their plans to publish 2 completely new D&D settings in the next couple of years?
That's actually a pretty good reason to suspect that this is not "The First World," since they would want to either reprint all of Fizbans material or create mutlibook dependency...
Why would you need to own Fizban's in order to use a First World setting book? I seriously doubt that there is literally anything in that book that would be necessary to play in a First World setting. Tasha's Cauldron of Everything talked about the First World before Fizban's did and the revisions to the Vistani before Van Richten's came out, and it's not like you need to buy TCoE to understand either of those books.
The WOTC design team is very anti-variant. It will likely just be "Standard Ren-Medieval D&D Setting" with Dinosaurs and more Giants
. . . Are you not familiar with Eberron? Or Ravnica? Or Theros? Or Spelljammer?
I see absolutely no reason why a First World or Prehistoric Setting book would be a "Standard Ren-Medieval D&D Setting with Dinosaurs and more Giants".
I mean, sure, there are a lot of "standard, pseudo-medieval D&D settings out there" (most created by TSR, not WotC, btw), but there are also quite a few major exceptions, and there's no reason to assume that WotC would make the First World/a Prehistoric Setting be one of those, based on the very concept alone.
Also, Primordials and Dinosaurs ate already Giant relayed, in the Primeval cosmic struggle between the Dragon gods and the Titans...
How are Dinosaurs related to Giants? I'm pretty sure they've been stated to be related to Dragons in past editions. Sure, in 4e, Primordials/Elementals/Titans were related to Giants, but wouldn't that also point to this book being a "First World" setting book that takes place during the Dawn War?