This deck tries to survive into the mid-game with Bonfire of the Damned, Lingering Souls, and single-target kill-spells. Then it plays powerful, hasty threats to quickly end the game.
Aurelia, the Warleader - Without any other creatures in play she's strong (with vigilance and flying, so you can block on their turn to race well), and with other creatures, it's almost always a guaranteed kill (especially with potential burn/reach in the tank for my next upkeep).
Spark Trooper - The lifegain is good against aggro, and the haste/damage is good against control. Paired with Silverblade Paladin it's individually 12 damage (with trample and lifelink attached to it).
Silverblade Paladin - Helps out the other cards, mostly. I can see some people cutting this, but the upside of silverblade->spark trooper/thundermaw/aurelia is incredible. It also represents 4 damage itself, which isn't too bad for a 3-drop.
Maybe move the Pillar's to the sideboard and sub them in for undying nonsense and put 2 Legion Loyalist in main board. You'll mainly use them as sorceries anyway but they can be fodder if you need it in the start.
Alright, finally a designated thread on slow Boros! I'm completely obsessed with trying to make a high-curve WR deck these days.
Two things on your build:
1) Some two-drop first strikers such as Elite Inquisitor, Ash Zealot or Precinct Captain work wonders against fast aggro such as Boros/Naya humans, white weenies and RDW/Rakdos. I can see that you prefer trying to burning them away, but it's a thought.
2) I really think that Silverblade Paladin needs some hatebears by his side. If he's the first creature you'll play, he's going to get removed immediately almost every single time.
I'm working on a deck that's meant to lie somewhere between aggro and midrange. I'd like to get defenses up for aggro instead of trying to burn it away, and I'd like to apply a certain amount on pressure from turn three and onwards, but still primarily focus on midgame finishers.