I've really been liking Stingscourger in a variety of matchups. He seems most significant against Reanimator and the like, but clearing a single blocker and attacking for 2 more for just 1 mana when you have a warchief out is sweet. He also clears a path for an early lackey. Cavern -> lackey into land -> stingscourger to bounce DRS/mom/nettle/delver/etc on T2 is so good.
Pyrokinesis is excellent, and I think of all the red decks that goblins is the best suited for it (thanks to ringleader making up for the card you lost to the alternate cost). I run 2 in the side and don't see myself taking them out any time soon. Could vary based on meta but it rocks against D&T and Elves, which seem to be everywhere.
I really want to try chalice, but since I haven't done so yet I can't really recommend it (or say to the contrary).
I actually was playing 4 colors for the past ~6 months up until the night before the open. I rarely had color fixing problems too.
However I cut white out because I found myself not wanting Thalia or RIP very often. I had 0 color fixing problems all day at the open, and don't expect it to ever be a common problem.
The reason I'm ok with Warchief + Tin Street is that it's pretty easy to play around. You generally know if you're going to be facing jitte/batterskull/etc before you lay down your first warchief, so you can prepare accordingly. I think it's too crucial to get rid of those pesky equipment cards ASAP so I like the low cost of Tin Street primarily for that reason as opposed to the 4CMC of Tuktuk. However, Tuktuk can be abused with Kiki and gives you another reason to like having a vial on 4. That's how I ended up liking the 1/1 split on them. I run so much artifact hate because I see far too many stoneforge decks in my local meta. There are a handful of MUD, painter, and Tezz decks floating around too.
It was really awkward playing against 0 stoneforge mystics through 9 rounds on Sunday, but I guess that's just up to chance. My artifact removal got sided out often, but there were a few matches where they were really helpful (such as blowing up feline's candelabra to stall long enough for a win).

