Red has relatively few Pauper cards worthy of discussion but they are absolutely going to have an impact. Let’s get to it.
Archaeomancer is already one of the most important cards in Pauper thanks to its interaction with Ephemerate. Ardent Elementalist takes the Blue card’s ability and staples it to an easier to cast body. Now in Nightscape Familiar decks it can become trivially easy to generate mana with this, some Familiars, some Izzet Boilerworks, and a Snap. And this is to say nothing of how well that deck can make use of Ghostly Flicker.
But that’s not all. We have already started to see some Mardu value decks based around the almost prohibitively expensive Revolutionist. While the body here might be significantly more fragile it is easier to get this on to the board and start generating value. This opens up another angle of deckbuilding, giving spell based control options to base-Boros decks. It also provides Jeskai Ephemerate decks additional redundancy in their engine while being easier to cast. This is probably the most important card for the format in Midnight Hunt.
These cards are always much closer to playable than they look, and the fact that this one is an instant helps quite a bit. It is possible that some Izzet Devious Cover-Up decks will want this, but there are probably just better options in Blue.
So another Kiln Fiend enters the format, only this one has an additional point of toughness. Izzet Blitz and other Kiln Fiend decks are always a threat and providing redundancy makes them that much better. We are approaching a critical mass of cards to make a mono-Red version of the deck a true threat, especially given the amount of card filtering we have seen made available lately. Mark my words – someone is going to be complaining about getting killed by this thing about a week into the set’s release.
In a format with Bonder’s Ornament and Myr Enforcer, this seems like it can see a ton of play. Remember those mono-Red decks I was talking about a minute ago? How many of them would love a bad Giant Growth/great Shatter split card? Quite a few, to be certain.