curious about what you think are brennan’s biggest strengths and weaknesses as a DM, and how CR and D20 highlight these differently? he definitely has a distinctive style and it works for me super well most of the time (not always) but seems to irk some people.
I think Brennan's biggest strength is that he has an excellent sense of what his go-to style requires, and DMs to fit that style. Brennan tends to go for pretty intricate mystery-esque plots where everyone is uncovering the various schemes and conspiracies. He is good at tying this into various character backstories and/or giving characters strong reasons to be invested in figuring out the mystery, and he is good at repeating information or highlighting it - as I've said, he does not really traffic in subtlety. You can't, in D&D that is very mystery-heavy, because your players really only have your words to go on and it's very easy to forget something. (Murph, who learned a lot about DM-ing from Brennan, has said something to this effect in D&D court on NADDPod a few times; there's no victory in tricking your players by not repeating yourself in describing a world that only exists in what you tell them). I think you can see it in Campaign 4, in which most pieces of information came out at multiple tables, and in which NPCs and Brennan aren't shy about highlighting something as important. I also think you see it in specifically where Brennan will bend the rules of D&D for dramatic effect - it is almost always in the service of more information (Message lasting longer; Speak with Dead permitting more of a conversation, etc). I will admit while I've seen a lot of D20 I do a much less close viewing, for various reasons, but he does do the same sort of repetition/willingness to speak out of "character".
I should add: I don't feel lack of subtlety to be a problem in actual play. I referenced the comparison to opera a while back; it is a medium and is usually in a genre that often works better when heightened. I think again this is why Neverafter doesn't work for me (while heightened is fine, obvious doesn't do well in horror) and I will say while I think Divergence pulls off its premise beautifully, it is a little weaker in terms of plotting compared to Calamity and Downfall because it's quite linear and straightforward and character-driven. I said elsewhere when comparing Matt and Brennan that I simply don't think Brennan would ever DM a campaign like the Mighty Nein (or rather: he could do the Aeor arc and Essek intrigue plots, so endgame Nein would be fine, but I don't think he could do early Nein because he doesn't really work with that light a DM touch). That's not a strength nor weakness, simply a difference of style, but it is illustrative of what is not his strength/inclination. Somewhat related to this is that you can Brennan has an improv and screenwriting background in that he does tend to end scenes on a button. I mean this positively - honestly, again, I don't mind lack of subtlety for actual play, and I think hammering the point home thematically isn't a bad idea in actual play if nothing else for the players, who are trying to understand the shape of the story they're in while they're in it, but I know it's not everyone's cup of tea. (For what it's worth, Aabria does this as well in her DM-ing.)
In terms of weakness...honestly? given the weaker D20 seasons and the fact that I fell off of the Wizard the Witch and the Wild One and never returned? I think it's that while I know Brennan has played in a bunch of different systems he has used D&D in a few cases where it was really not the right game. He's actually quite good with systems/mechanics and his add-ons in, eg, Campaign 4 or Fantasy High Junior Year have been great, but like, Neverafter needed, frankly, everything to be different including a more horror-forward system, and WBN needed something more rules-lite and sweeping. CCOD has been great in using a different system, and I've also liked the Kids on Bikes hacks from D20, and Starstruck, so I hope he gets better at using mechanics that better fit the story instead of leaning on D&D beyond its capacities.
I think a milder weakness, and this is also true of Neverafter and something I will admit I keep an eye on in some aspects of Campaign 4: I am not a creative by profession. I have a great love of many forms of art. But when art, and especially art reliant on words, becomes about the importance of art, or a story becomes about the importance of stories, it can be done well! I also find it can also get, well, very masturbatory very quickly. This is kind of the secondary problem with Neverafter, especially since it didn't really do much with that thesis after the archetype reveal after the TPK and then just ran through a bunch of Dark (TM) fairy tales. I am not too worried about Campaign 4 in that I genuinely feel Brennan and Liam have a really good vision for what the play means, and it is genuinely important, and they are not losing sight of like, in-world consequences. But it is something I personally tend to keep an eye on as "thing that could be really great, or go off a cliff very quickly."