I don't think is as competitive as other Taxes build but I enjoy brewing things and I wasn't really happy with other RW lists that I have seen before. I only played this in Xmage but it was really fun and better than I expected.
I wanted to fill the deck with a lot of must-answer threats that red provides: Grim Lavamancer, Goblin Rabblemaster and Pia and Kiran Nalaar will win the long game if they are left unchecked. Thanks to protection blinks, Thalia and of course Moon Man this happens quite often. Ajani Vengeant fills the taxing plan while also being a win condition by itself. Really, T3 Moon Man followed by T4 Ajani to start tapping out opponent is huge. 6 removal spells + Ajani's Helix + Flickerwisp + Pia makes combat really easy to attack with a huge Rabblemaster to close the game faster than in other builds
Pia Nalaar it's okay. By itself is worse than Blade Splicer, but flying tokens + mana sink + utility for topdecked Aether Vials makes her pretty good. Dire Fleet Daredevil was a little bit dissapointing.
As for SB, having access to 10 removal spells + 2 sweepers against creature decks is huge. Anger is worse than Settle but the -1 mana cost and the backup plan for RiP against Dredge convinced me to play it. As for Hazoret and Chandra, they're just another difficult to remove threat that can win the game alone, for grindy matchups. Maybe they even can make the cut to MB by cutting Ajani or P&K.
I just wanted to share this list and ask for your thoughts. I would be very pleased if someone tests it and has the blast that I had online with this list.