How late in the design process were badgers replaced with raccoon? Was the decision to make Gruul's mechanic expend already made by the time the swap was decided on? Or did market testing show the audience's preference before any of that was locked in?

The change was made mid vision design. I’m not sure when expend first got added. It was there at the handoff, although unnamed.

We've seen very few cards as of yet, but are the following mechanics exclusive to their faction: Valiant (Mice), Thresold (Rats), Expend (Racoons), Forage (Squirrels)? Or can we expect to see at least a little of (some of) them in more colors?

Those four mechanics are unique to one animal archetype.

May I request some detail about why expend is templated this way? I think it's a very cool mechanic, but it reads like it cares about you doing something four times rather than having done something a fourth time.

It’s not about doing it a fourth time. It’s talking about casting some number of spells with a combined mana value of 4 or greater.

" I am interested in feedback if you all like the idea of a showcase set. If the answer is yes, are there other themes you'd like to see?" I would like to see the idea expended on, yeah. Some ideas of showcase themes: -A tournament or competition; -a trapped plane/prison plane that captures people from across the multiverse; -a clash between two or more planes.

There are many ways to do a showcase set. Everyone should remember that when I say a “showcase” set I mean, the set is built around a theme, and then we bring characters, and potential other things like objects, there that fit that larger theme. Next year’s omenpath set is Tennis and it’s a different kind of set, what I’m calling a travelogue set" where there is something that takes place over multiple worlds, in Tennis’ case a race.

Since alternate frames and treatments seem to cost less than something like DFCs, do you have an estimate on the upper ceiling for number of alternate treatments in a set? Is it gated by another resource?

I said alternate frames have a people hour cost, but not a lot of outside expenditure.I didn’t talk about art though. That’s the biggest expenditure of alternate treatments.

If it's "not on Dominaria," does that mean Core Set 2018 will be set on one single plane? I think it would be cool and perfectly doable to have a core set revisit for example Zendikar, Alara, etc. (although I know that would also "expend" a revisit of that plane.)

The question was about the fall set, not the Core set.

Energy spell having a use outside of energy either because they still have another effect, or because they give you energy so you can spend it for the spell's effect, doesn't make this non-Parasitic. With the exception of Evermind, you can still play Splice onto Arcane spells in decks with no other Arcane spells, and it's often done with Through the Breach and with Desperate Ritual, in different Modern decks.

I never said Energy wasn’t parasitic. I said it was significantly less than parasitic than Splice onto Arcane. Splice onto Arcane is an additive (and powerful) ability. Spells with it have to pay extra for the ability so you have very little incentive to play a Splice spell you never plan to splice.Energy, in contrast, gives you an ability with the proper amount of energy to use that ability. Because there’s an Energy economy (each energy expenditure values Energy at the same rate), there is less requirement to play other Energy cards. Yes, there is some Energy synergy in that you get more choices, but that synergy is worth far less than the ability to repeatedly get an effect without costing a card.

Why did upkeep costs mostly go away? On top of being flavorful (needing to expend mana to maintain an effect), it parallels outlast in that it's more strategically interesting to decide up front what some of your mana is being spent on this turn.

Because all-downside mechanics aren’t all that popular. Upkeep also had memory issues. We still do it occasionally but very infrequently.

something I never figured out. Why get rid of the Magic Rewards system? As a person with a Sarkhan Vol DCI card I have to say it was an amazing program and I'm sad to see it's no longer implemented.

The blunt answer was it was insanely costly and, in the end, didn’t justify the expenditure. We decided to use the money on multiple other programs instead.

What do you think about token creature generation in black? Expendable fodder seems like something black would be all over. But as I look through Gatherer I find very little for black that's competitively cost enough to play in eternal formats, even more casually.

Black does have token making cards but they tend not to be too aggressively costed as black is not a primary token making color (they are white and green). To answer the question preemptively, blue is not primary either but it seems to have the special power that it tricks R&D into pushing its cards.