The serious events do tend to have some neat decks, I like that Kevin came out with a bunch of new cards and managed to top 8 with them (what a master), I do think some of that has more to do with the player than the cards. That all aside, I think Spell Queller is definitely an interesting card with a lot of stuff going for it. I am not as convinced about tamiyo, but there might be more good outcomes for that.
All that aside, and I am glad you point out the card, I think Stoneforge Mystic is amazingly well positioned at the moment, though no maindeck Jitte from Kevin gives me some pause, as the card is SUPER good today. I think we might be in a position to see even more interesting things in vintage. I was really impressed by Bryan Fisher's take on Burning Omni Oath from that top 8, for example, helping some of the consistency problems of omni Oath, if maybe not solving all.