But there's no denying that Critical Role is popular and has devoted fans. There are a surprising number of people willing to fork over $125 for a deluxe art book about someone else's campaign, for example. You can also buy a tarot deck based on the characters from the Critical Role campaign, Critical Role dice, and a campaign sourcebook about the campaign world created for the Critical Role livestream. What might you get out of the latter if you don't happen to belong to their fandom?
Reading the Tal'Dorei Campaign Setting book feels exactly like reading a high-production values version of someone's notes for their homebrew vanilla D&D campaign world, which is more or less what the book is as a product.
The world-building relies on well-established conventions--the elves were the first people of the land, they value the arts, grace, and magic, etc.--and very little is surprising. There are places named with the usual sort of compound wording: Whitestone, Daggerbay, the Frostweald. And others that seem like they could have been pulled from any number of fantasy novels you've already read (and forgotten): Drynna, Tormor Falls, the Shifting Keep. Even that extraneous apostrophe in Tal'Dorei is charmingly homespun. You can sometimes see the seams where the time-honored tradition of taking something wholesale from another campaign, filing the serial numbers off, and inserting it into your own game has been practiced; the deities in Tal'Dorei are obviously the gods of 4th edition Dungeon & Dragon's Dawn War pantheon given a quick renaming: the Raven Queen becomes the the Matron of Ravens, Bahamut becomes the Platinum Dragon, Lolth becomes the Spider Queen, etc.
The mechanical bits also seem like natural extensions of someone's home game. The new Backgrounds aren't mind-blowing wild, but they're well situated within the context and flavor of the setting. Similarly, the new class options that are introduced, such as the Way of the Cobalt Soul monk or the Juggernaut barbarian, evidence a bit of the hesitancy to add things to the game that overshadow the official options you often find in player-facing homebrewed options. None of the classes are strictly bad per se, but they seem to be either overly specific in function or occupying a space on the lower end of the power spectrum so as not to throw anything out of whack.
Similarly, the Optional Campaign Rules are explicitly called out as natural outgrowths of the house rules from their campaign: "For those who have watched along with our adventures, you may see some of these optional rules as familiar. Many of the elements included in this chapter are based on or retooled versions of the house rules we tried within our own campaign" (118). The optional rules do feel "lived in," like they were rulings that came up in response to the baseline system not quite providing what they wanted it to. Potions can be quaffed in combat without that taking up an entire turn, resurrection magic is more challenging, etc. Nothing that radically restructures the game is included here; rather, it all feels like common sense rulings to accommodate the size of their gaming group and the style of play they prefer.
The art is of the quality and style you would expect, and the book's production values are top notch. Ultimately, my take-away is that this is a very solid vanilla D&D setting. And I know some people will scoff at the idea of another vanilla setting, but I'm not joining that chorus. Although I prefer my own bespoke, not-the-usual-fantasy settings, vanilla has its place. If we're honest, we'd probably have to admit that there have been more D&D campaigns set in vanilla fantasy settings than anything else, and that the people who have played in them probably enjoyed them immensely because vanilla fantasy is what they want.
This is perfectly serviceable vanilla; if you're already into Critical Role, this is probably a preferable alternative to the Forgotten Realms or Greyhawk on the merits of familiarity alone. But you know what I really like about this book, though? It's lack of wild invention makes the idea of homebrewing your own setting look easy. Sure, your work probably won't end up getting the full-color treatment from Green Ronin, but it still looks like something approachable and possible. And maybe even fun. Whether you want to go wildly inventive or French vanilla, this book says "We made this and had fun, so can you."