I think Kor Firewalker is a bit too much to put in the main because it can become a plain old 2/2 for 2 in lost of match ups, and also especially because you have a card like Student of Warfare sitting in the sideboard for no reason. Unless the meta that you play in the heavily red, I would suggest main boarding the Students over the Firewalkers. Kor Skyfisher would also be a good option to stick into that slot. It can pick up allies, your own enchantments. And if you're mana-screwed, it becomes a 1 cost 2/3 flyer. Awesome. Speaking of land, is 23 working out for you? My build has like, 21 and that works for me pretty well.
Well main reason Kor Firewalker are main because where I play many of the decks are either mono-red, Jund, or black-red. So where I play it helps to shut down red. Also Students are side because I have a tendency to spend the mana on leveling him which inadvertently slows my game way down. On top of all that students are a nice little one drop that I can get out if need be and just block. Plus I need to fix the deck. I forgot to put the two students I run main. (fail) and the 23 lands i run work pretty well for me. It ensures i can get my Banesleyer out. Plus if I get my Luminarch Ascension out I have plenty of mana to make 4/4 Angels. I have done really well with this deck. Every time that I have played this deck at FNM I have top foured. I have gotten 1st twice. In my book that's pretty decent since I have been playing for about 6 months. This deck is an adaption of the other mono-white deck that is on here.
sorry I was on the wrong profile...but I still mean the same