Looking forward to your discussion on investigate. Investigate is such a beautiful mechanic. I'm glad you just did your podcast on good game mechanics, because investigate hits nearly every point you made: It's flavorfully resonant, it solves inherent problems in the game (card flow and mana flood), it gives players free things. And it's played as well as it reads.
Is this the right spot? Your new podcast linked to this thread.
I'm really sad to hear that you're stopping Remaking Magic. There are plenty of podcasts out there dedicated to playing the game of Magic, all the different formats, and the flavor, but there aren't any others that talk about the design aspect like you do. I've learned a lot from listening to this podcast, and I always enjoy the new insights that you bring every episode. I hope that you'll occasionally come back to talking about Magic design in the future, maybe in writing. Best of luck on your future endeavors.
As to the mechanics you discussed this episode.
I was quite skeptical of delirium when it first came out, but after playing with it, I've come around to really like it. It plays really well for all the reasons you mentioned. It adds an element of tension to the game, and it shapes the format in a fun and interesting direction. I think a large part of the reason I wasn't sold at first was because I think Wizards made a really poor choice for the first delirium card spoiled. It was Mindwrack Demon from the Blessed vs. Cursed duel decks. Having a drawback that turns off with delirium is an interesting application for players that are already familiar with the mechanic, but it does not create a good first impression for the mechanic's potential, nor is it a good mythic rare or Duel Deck marquis card. They really could have done better there.
I was in love with investigate the moment it was spoiled, and the gameplay did not disappoint. It hits all the notes of what makes a good mechanic that you talked about previously: it's super flavorful, it gives players free stuff, it solves mana screw and encourages card flow. What Dan said about investigate being a role filler rather than exciting on its own makes sense on paper, but I find that in practice the accumulation of clue tokens and the drawing of cards from them has been really fun for me. Maybe it's just me. I have an inordinate fondness for mechanics that convert one resource to another, such as delve and convoke, so building up clues and converting them along with mana to cards really appeals to me.
Dan hit on the problem with skulk right on, which is quite impressive given that you hadn't played the set when the podcast was recorded. Skulk doesn't do enough on any creature with greater than 1 power to justify its existence. It plays decently, but isn't particularly impactful, and the design space is far too narrow. Really impressed that you picked up on this so early.