Possible replacements:
-2 royal sage, +2 soul split not tested yet
-2 firebolt -2 royal sage, +2 execute + 2 cloudrest illusionist

suggestion: If you face merric often switch to executes

Possible combos
markedman + atro
markedman + pit lion
markedman/ quartermaster + conspirator card draw
(markedman+ soulsplit)

Gameplay:

its a curve deck so try to curve out as best as possible, establish board presence by turn 4-5 to play fervor golden saints, you don’t need and you probably cant push lot of dmg early game, atro is your finisher so you need to be able to play it on curve.

Against aggro: you play the defensive role, you should not race unless its your only way out, control field lane and save removal taunts for shadow lane when/if they run out of cards you win, dont worry aggro is a joke so you wont face aggro decks anyway

Against midrange: Most midrange decks suffer when fall behind, fight for the board and play to your golden saints, if you snowball them you will win, race is an option if your hand allows you to do so, if you have the ring always save a charge for turn 8 atro, midrange games are decided by atro a lot, if you dont have the ring be sure you can answer the field lane on turn 8-9, You should consider use the 0/2 taunts to block attacks and keep your hp high or preserve a minion on board instead of draw with conspirator

Against Control: Most of the control decks will die to atromancer control mage can answer atro so you need to fish for divine fervor they cant deal with support so your atro cant be answered anymore, also golden saints should be game wining with fervor up, you can keep your markedmen for atro burst finisher